Five power supplies compared

I‘VE SAID IT before and I’ll say it again: power supplies are continually the most neglected PC component. It boggles my mind how many systems I see with swanky LCD monitors, high-end graphics cards, screaming-fast processors, and flashy artistic modifications all powered by no-name power supplies that are often the root of stability problems. Would you dare put cheap gas in a Porsche? Of course not, yet I continue to see enthusiasts putting cheap power into their high-end PCs.

I suppose the assumption is that all power supplies of similar wattage are created equal, but that couldn’t be farther from the truth. PC power supplies can differ in not only more obvious environmental attributes like noise and heat levels, but also in the quality of power they deliver.

Last year, I compared four different power supplies from Antec, Thermaltake, and Vantec. Antec’s TruePower line came out as our Editor’s Choice in that comparison by delivering tight DC voltage tolerances with low noise levels. Today, I’ve rounded up five brand-new power supplies from Ahanix, Antec, Enermax, Vantec, and Zalman to compare with each other and our previous favorite. I’ve updated our power supply testing gauntlet, too. Not only will we be looking at DC voltage tolerances and noise levels, we’ll also take a peek at each power supply’s impact on system temperatures and measure its AC ripple voltage.

Which power supply stands out from the competition as being the quietest, coolest, and cleanest source of PC power? Read on to find out.

The specs
Power supplies are usually bunched together based on their total output wattage, but there’s more to wattage than total output. Today we’re dealing with 400 and 550W power supplies, and there’s quite a bit of variety when it comes to distributing that total wattage over available voltage lines.

Maximum output (W)

DC Output +3.3V +5V +12V -5V -12V +5Vsb
Ahanix SilenX 400W 52.8 200 336 1.5 9.6 10
200 336
Antec TrueControl 550W 105.6 200 288 2.5 12 10
Antec TruePower 550W 105.6 200 288 2.5 12 10
Enermax EG651P-VE(FMA) 550W 118.8 180 432 5.0 12 11
200 432
Vantec Ion 400W 85.8 200 192 12 4 12.5
380 28
Zalman ZM400A-APF 400W 92.4 200 180 1.5 9.6 10
380 20

While Enermax, Vantec, and Zalman’s power supplies all share voltage between the 3.3 and 5V rails, Antec’s TruePower and TrueControl models have dedicated output circuitry for each rail. This dedicated output circuitry comes in handy when a system has an unbalanced overall load that’s biased towards the 3.3 or 5V line. If the 3.3 and 5V lines don’t have to share wattage between them, each line can be loaded to its theoretical limit.

Overall, Enermax’s EG651P-VE(FMA) offers more wattage on the 3.3 and 12V rails than any other power supply we’re looking at today, but only 180W on the 5V rail. Ahanix’s SilenX is a little weak on the 3.3V line, but its maximum 12V wattage is quite strong. Vantec and Zalman’s offerings, on the other hand, offer relatively low 12V wattages but plenty of power on the 5V line.

For reference, here are the maximum output currents for each power supply’s output lines:

Maximum output current (A)

DC Output +3.3V +5V +12V -5V -12V +5Vsb
Ahanix SilenX 400W 16 40 28 0.3 0.8 2.0
Antec TrueControl 550W 32 40 24 0.5 1.0 2.0
Antec TruePower 550W 32 40 24 0.5 1.0 2.0
Enermax EG651P-VE(FMA) 550W 36 36 36 1.0 1.0 2.2
Vantec Ion 400W 26 40 16 0.8 1.0 2.5
Zalman ZM400A-APF 400W 28 40 15 0.3 0.8 2.0

Other than Enermax, whose EG651P-VE(FMA) offers the same maximum amperage on the 3.3, 5, and 12V lines, manufacturers tend to offer higher currents on the 5V line.

Theoretical specs are only so exciting, so let’s dive in and take a closer look at what each power supply has to offer.

Ahanix’s SilenX 400W

Manufacturer Ahanix
Model SilenX 400W
Price (street) US$99
Availability Now

Ahanix’s SilenX is probably the most spartan power supply in this comparison, which makes it a good place to start. Power supplies don’t necessarily need frills or bundles to complete the package, so the SilenX should be OK without them, so long as its performance and price are competitive. Aesthetically, there’s not much to see with the SilenX; it looks like, well, a power supply.

The SilenX has an external power switch, which a surprising number of power supply manufacturers seem to leave out. A single 80mm fan cools the unit and generates a scant 14 decibels of noise, according to Ahanix. We’ll see in a moment just how quiet this power supply is when it’s running in a complete system.

To make up for its single-fan design, Ahanix gives the SilenX plenty of internal venting. Without a second fan, the SilenX should be quieter than dual-fan power supplies. However, the SilenX’s single fan may have to spin faster than a pair of fans working together might, possibly generating more noise in the process.

As far as cables go, the SilenX is complete but not extravagant. Cables are 20 inches long, which should definitely be long enough for most applications and cases, but may be a little short for double-wide or full-tower cases with hard drive racks near the bottom. The SilenX 400W offers six four-pin Molex connectors and a single floppy plug in addition to a full set of motherboard power connectors. None of the SilenX cables are sheathed, but they’re all zip-tied to reduce tangling.

Antec’s TrueControl 550W

Manufacturer Antec
Model TrueControl 550W
Price (street) US$110
Availability Now

Antec’s TruePower 550W won our last power supply comparison, so we have high hopes for the TrueControl 550 this time around. As far as I can tell, the actual power supplies inside the TruePower and TrueControl 550 are identical. There are a few cosmetic differences here and there, and the TrueControl has a few extra goodies included. As far as the actual power supply units go, though, I can’t find any significant difference between the two. We’ve already seen that the two share identical current and wattage specs and Antec’s dedicated output circuitry.

Like the TruePower 550, the TrueControl is a plain-looking power supply. Cooled by a 90mm internal fan and a 80mm external fan, the TrueControl is the first of three dual-fan power supplies in this comparison. Fan speeds are controlled by the power supply, which cranks up and throttles back the RPMs as needed. The minimum fan speed can also be controlled using the TrueControl’s drive bay insert, which I’ll get to in a moment.

Like the other power supplies in this comparison, the TrueControl 500W has an external power switch. The unit is also outfitted with an external four-pin Molex connector, though I can’t think of why anyone might need four-pin power on the outside of a case.

The TrueControl 550 isn’t as heavily vented internally as some of the other power supplies we’re looking at today. Fewer vents could make it harder for the TrueControl to cool the interior of a case, forcing its fans to spin faster and louder.

Antec is the only manufacturer in this comparison to offer black power connectors on its power supply, but since the TrueControl itself isn’t black, I’m left scratching my head. The black motif extends to the sheathed motherboard power connector and zip ties, too, but the power supply should really be painted to match.

Whatever Antec’s aesthetic intentions were with the TrueControl, they’ve given it plenty of cable. The motherboard connector stretches a full 21 inches from the power supply, and four-pin Molex connectors reach just over 32 inches. In total, the TrueControl 550 has seven four-pin Molex connectors and two floppy connectors. There are also two four-pin Molex “Fan only” connectors that will keep case fans spinning at the same speed as the power supply’s temperature-controlled fans. These extra two Molex connectors shouldn’t be used with anything other than case fans, but I wonder if they might not be suitable for internal lighting that would get brighter or darker depending on system temperatures.

As its name implies, Antec’s TrueControl lets users do a little tweaking. A 5.25″ drive bay control panel is provided with the TrueControl 550, so users don’t have to crawl around behind their case to fiddle with the power supply’s settings.

Like a few other power supplies on the market, the TrueControl 550W offers users a level of control over the power supply’s fan speeds. The fan speeds are still largely controlled by the power supply, which ramps up the RPMs as temperature levels dictate. However, users can manipulate the power supply’s minimum fan speed with a small knob on the front of the drive bay panel.

In addition to offering control over minimum fan speed levels, the TrueControl offers voltage tweaking via the drive bay insert. Small screws on the front of the drive bay can be turned to raise or lower the voltage level of the 3.3, 5, and 12V rails with either a screwdriver or a removable knob that pops out of the drive bay. The availability of voltage control should allow users to fine tune each voltage line to perfection, and as far as I know, Antec is the only manufacturer to offer such a feature.

It’s important to note that one can easily damage PC components by either under- or over-volting them. In the hands of an inexperienced user, TrueControl can actually do more harm than good, which is probably why a screwdriver is needed for voltage manipulation. The voltage screws aren’t something you’d want to turn accidentally.

Enermax’s EG651P-VE(FMA) 550W

Manufacturer Enermax
Model EG651P-VE(FMA) 550W
Price (street) US$126
Availability Now

If I were judging purely on looks, Enermax’s 550W EG651P-VE(FMA) would definitely take the cake. While certainly not flashy, the power supply has a glossy, deep-blue finish that’s nicer than most case treatments. The dark blue EG651P-VE(FMA) probably isn’t the best cosmetic match for an all-aluminum aesthetic, but I’d love to find a case that matches its color.

The EG651P-VE(FMA) uses an 80mm rear fan and a 90mm bottom fan—not only to keep the power supply cool, but also to vent air from the system. Both fans are variable-speed units controlled by the internal power supply temperature, but the rear fan speed can also be adjusted with a knob mounted on the back of the power supply. Having the knob at the rear of the power supply ensures that it’s accessible without having to pop off any case panels, users will still have to crawl behind the back of the case to use it. Because only a few of the power supplies we’re looking at today feature user-controlled fans at all, it’s hard to gripe too much about where Enermax puts the fan speed knob. The knob turns freely, providing plenty of fine-tuning precision, and there’s even a notch to help you know just how close you are to the lowest or highest fan speed.

There’s plenty of venting at the rear of the EG651P-VE(FMA), and the absence of a third fan should keep the unit’s noise levels low. Lower than the others? We’ll soon see.

The EG651P-VE(FMA) is the only power supply in this comparison to not only sheath the main motherboard power connector, but also the other auxiliary motherboard power connectors. It’s not a big deal, really, but this nice little makes the EG651P-VE(FMA) stand out. The individual Molex cables are neatly zip-tied, too.

Ready to stretch across the confines of even the largest full tower cases, the EG651P-VE(FMA)’s motherboard power cables are 20 inches long and the Molex cables stretch a full 33 inches. With eight Molex and two floppy connectors, there are plenty of plugs for massive RAID arrays. There’s even an extra Molex connector that brings the four-pin plug total up to nine, should you need it.

Like most of the other power supplies in this comparison, the EG651P-VE(FMA) comes with a set of four screws. Enermax also throws in a Molex splitter that can power two Serial ATA hard drives and an “Enermax Power Inside” sticker for those who want to advertise their power supply investments. Because it’s the most expensive power supply we’re looking at today, I’m going to whine about the fact that Enermax doesn’t include any zip ties or cable binders in the box. Yes, the EG651P-VE(FMA)’s cables are neatly sheathed and zip-tied to reduce tangling, but it would have been nice for Enermax to include a couple of extra zip ties for securing cables to the interior of a case.

Vantec’s Ion 400W

Manufacturer Vantec
Model Ion 400W/font>
Price (street) US$64
Availability Now

At only $68 online, Vantec’s Ion 400W is the cheapest power supply in this comparison by nearly $30. Still, the Ion manages to pack in a few features that even its more expensive competition forgets. On the surface, the Ion looks rather plain, especially next to Vantec’s all-black “Stealth” line of power supplies. Power supplies don’t have to look good, but since Vantec makes a lot of modding and lighting gear, I expected the Ion to have at least a little visual flair.

Breaking from tradition, Vantec uses 80mm fans for both the Ion’s internal cooling fan and rear exhaust. The internal 80mm fan will have to spin a little faster to move as much air as a 90mm unit, but the impact on overall noise levels may be negligible.

To control the speed of the Ion’s two fans, Vantec offers users three options with a switch at the back of the unit. Users can set the fan speed to “auto” and let the power supply decide when to spin up or spin down the fans, or choose arbitrary “low” or “medium” fan speed settings. Without a “high” fan speed setting, the Ion’s smaller 80mm internal fan may have a rougher time sucking hot air from a system, but it should do a better job than single-fan power supplies.

Also gracing the back of the Ion is a standard three-prong outlet for connecting peripheral devices like monitors, speakers, printers, and so on. Currently, I’m running most of my machines off a tangled array of extension cords and power bars, so an extra power outlet is certainly welcomed.

The Ion 400W’s internals aren’t as riddled with vents as some of the other power supplies we’re looking at today, but the unit does have more internal venting than Antec’s TrueControl.

Despite its relatively low price, the Ion 400W delivers more cabling than any other power supply in this comparison. The sheathed motherboard power connector stretches a full 24 inches from the power supply, and Molex connections are available 36 inches from the unit. The Ion offers a grand total of nine four-pin Molex connectors and two floppy connectors.

The Ion 400W’s box advertises the fact the power supply is “SATA Ready!!!” That’s technically correct, but Serial ATA connectivity is offered through Molex power adapters rather than with native Serial ATA power plugs. Since Serial ATA drives have yet to take the market by storm, it actually makes a lot more sense to use power adapters and retail four-pin Molex connectivity.

In addition to a couple of Serial ATA power adapters, Vantec packs the Ion’s box with four mounting screws and five small zip ties. Those extras probably add only pennies to the overall cost of the power supply, and they’re definitely worth having.

Zalman’s ZM400A-APF 400W

Manufacturer Zalman
Model ZM400A-APF 400W
Price (street) US$92
Availability Now

Despite claims by all manufacturers that their power supplies are nice and quiet, Zalman takes things one step further by completely stealthing out the ZM400A-APF in black. The ZM400A-APF should look great in dark cases with neon or UV lighting, though the power supply’s finish isn’t glossy like Enermax’s EG651P-VE(FMA) treatment. Being the only Goth in the crowd does make the ZM400A-APF stand out, though. With a little chrome trim, it could be the power supply your mother warned you about.

Zalman relies on a single 80mm exhaust fan to keep the ZM400A-APF cool, which should do wonders for noise levels, but will probably result in higher case temperatures. The rear exhaust fan is temperature-controlled, which should make the ZM400A-APF even quieter when you’re listening to MP3s.

To make up for its lack of a second internal fan, the ZM400A-APF is heavily vented to facilitate air flow. Will it be enough? We’ll see in a minute.

Zalman doesn’t sheath the ZM400A-APF’s motherboard power connector, which is a little disappointing. The unit really needs cables like those found on Antec’s TrueControl if Zalman wants to keep up the black motif.

As for cable lengths, the ZM400A-APF offers 20″ motherboard and Molex cables. For most applications, 20 inches should be long enough, but the ZM400A-APF may not have enough reach for RAID arrays mounted at the bottom of full-tower or double-wide cases.

Breaking from the zip tie crowd, Zalman includes four Velcro cable binders with the ZM400A-APF. It would have been nice if the Velcro were black, but at least it’s reusable. Zalman also throws in a Molex splitter that can be used to power all manner of three-pin auxiliary fans. Unfortunately, those fans won’t be temperature-controlled like the ZM400A-APF’s exhaust port.

Our testing methods
All tests were run three times, and their results were averaged, using the following test systems.

Processor AMD Athlon XP 3200+
Front-side bus 400MHz (2x200MHz)
Motherboard DFI LANParty NFII Ultra
Chipset NVIDIA nForce2 Ultra 400
North bridge nForce2 Ultra 400 SPP
South bridge nForce2 MCP-T
Memory size 512MB (2 DIMMs)
Memory type Corsair XMS3200 PC2700 DDR SDRAM
Graphics ATI Radeon 9800 Pro 256MB
Audio M-Audio Revolution 7.1
Storage controllers

Adaptec 29320-R


Maxtor 740X-6L 40GB 7200RPM ATA/133
Maxtor Atlas 10K SCSI
Maxtor Atlas 15K SCSI
Seagate Cheetah 10K.6 SCSI
Western Digital Raptor WD360 Serial ATA

Operating System Windows XP Professional SP1

Voltage tests were conducted using a Pico ADC-212/3 digital oscilloscope while the test system idled and was under a load consisting of a looped 3DMark03 demo with Folding@Home running in the background. The same idle and load conditions were also used in our noise level and temperature tests.

For noise and temperature testing, a second test system was used, consisting of the following components enclosed in Antec’s Lanboy case with no additional cooling fans other than those on the processor, graphics card, and power supply. A stock cooler for the Athlon XP 2100+ was used.

Processor AMD Athlon XP 2100+
Front-side bus 266MHz (2 x 133MHz)
Motherboard Tyan Trinity KT400
Chipset VIA KT400A
North bridge VIA VT8377
South bridge VIA VT8235
Memory size 512MB (2 DIMMs)
Memory type Corsair XMS3200 PC2700 DDR SDRAM
Graphics ATI All-in-Wonder 9700 Pro

Samsung Spinpoint SP1203N 7200RPM ATA/133

Operating System Windows XP Professional SP1

Temperature measurements were taken using Motherboard Monitor 5. The Trinity KT400’s integrated temperature sensors and noise levels were measured using an Extech 407727 digital sound level meter. Both noise level and temperature measurements were taken after the system had been idling or under load for 15 minutes. The ambient temperature in the underground benchmarking sweatshop during testing was a steamy 27.5 degrees Celsius, which is a little higher than what I hope most of you have to put up with, but should be a good extreme environment for the power supplies.

Because users can easily manipulate the TrueControl 550W’s voltages, it’s a bit tricky to test. To simulate a likely real-world calibration, the TrueControl’s 3.3, 5, and 12V rails were set as close to 3.3, 5, and 12V as possible using a digital multimeter and the motherboard’s BIOS to verify the voltage on each rail. Since one isn’t likely to manipulate voltages on the fly often (or even at all) once they’re initially set, the TrueControl’s voltages weren’t tweaked after testing began.

We used the following versions of our test applications:

The test systems’ Windows desktop was set at 1024×768 in 32-bit color at a 75Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

DC voltages
To test each power supply’s DC voltage tolerance, I measured the DC voltage of the 3.3, 5, and 12V rails using the digital oscilloscope over a five-second time interval. Since none of the power supplies had any significant peaks or valleys over the five-second interval, I’ve presented the average voltage over that time.

On the 3.3V rail, the EG651P-VE(FMA) and TruePower 550W show a noticeable difference between load and idle voltages, but both are within their respective tolerances. The ZM400A-APF nails 3.3V on the dot at idle, while the Ion and SilenX 400W are both quite close.

Zalman’s ZM400A-APF hits the 5V rail perfectly, but all the power supplies are evenly matched and easily within their advertised tolerances. They all show relatively equal voltages under load and at idle, too.

The 12V rail shows a little more variance, but all the power supplies are well within their tolerances.

Overall, it’s a little disappointing to see the TrueControl not nailing the voltages perfectly. Using a digital multimeter and BIOS to set the TrueControl’s voltages isn’t the most precise calibration method, but it’s definitely more accessible than using a $500 oscilloscope. I suspect that the majority of enthusiasts won’t even bother with a digital multimeter and will instead set the TrueControl’s voltages using their motherboard’s BIOS or perhaps Motherboard Monitor to verify the voltage on each rail.

AC ripple voltage – 3.3V rail
PC power supplies must convert an AC power source to produce DC voltages, but a little bit of AC voltage always sticks around. This “Ripple” voltage is residual effect of the AC-to-DC conversion process, and the less ripple, the better. Because ripple content varied so much in my testing, I’ve included timescale graphs showing the ripple over a 10ms time interval.

It’s easy to see that the Ion 400W has the highest ripple on the 3.3V rail, especially since the other power supplies have similar ripple content. Overall, Enermax’s EG651P-VE(FMA) has the lowest ripple content under load and idling, while both Antecs, the SilenX, and ZM400A-APF are locked in a virtual tie for second place.

AC ripple voltage – 5V rail

The Ion 400W has more ripple than the competition on the 5V rail, too. Again, the ripple content of the other power supplies is very close.

AC ripple voltage – 12V rail

On the 12V rail, the Ion has lots of ripple once again. The other power supplies continue to be closely matched, but the edge is going to have to go to the TrueControl this time around. Barely.

Temperature levels

In our system temperature tests, Antec’s TrueControl 550W produces the lowest case temperatures at idle and under load, but only with its fan speed all the way up. Enermax’s EG651P-VE(FMA) produces the second lowest set of temperatures regardless of which fan speed is used, and the TrueControl 550W’s low fan speed setting slots it in fourth place.

Overall, dual-fan power supplies do better in our case temperature tests. However, the Ion’s dual 80mm fans don’t help it run any cooler than the single-fan ZM400A-APF. Interestingly enough, Ahanix’s single-fan SilenX 400W actually produces relatively low case temperatures at idle, but loading the system instantly ramps up temperatures.

The processor temperature test results follow the case temperature results exactly. The dual-fan Enermax and Antec units rule the roost, but are they louder than the single-fan power supplies?

Noise levels

Vantec’s Ion 400W has the lowest noise levels an inch from the top of our Lanboy case. Ahanix’s SilenX is a little louder than the Ion, but not by much. Antec’s dual-fan TruePower and TrueControl 550W units are rather quiet, too, though the TrueControl gets a lot louder with higher fan speeds.

As a single-fan power supply, the ZM400A-APF’s noise levels are a little disappointing. The power supply is relatively quiet at idle, but its temperature controlled fan spins a little louder under load than the competition.

At the rear of the case and outside the direct path of air flow, the power supplies stack up much like they did when we measured at the top of the case. Vantec’s Ion continues to be the quietest of the lot, followed by Antec’s TruePower and TrueControl models. Ahanix’s single-fan SilenX drops a little in the rankings this time around.

To simulate operation in a silent PC, I also connected the power supplies up to a passively-cooled system whose only sources of noise were the hard drive and whatever background noise lurks in my basement suite at 2AM.

With barely any background noise clouding our perspective, the single-fan power supplies are all closely matched. The dual-fan power supplies don’t do too badly here, but Vantec’s Ion is definitely quieter than the others, even with its medium fan speed setting. The high fan speed setting on Enermax’s EG651P-VE(FMA) is louder, but not overbearing. Antec’s TrueControl 550W, though, is almost a Dustbuster at its highest fan speed setting.

Trying to pick a clear winner out of five closely-matched power supplies isn’t easy. To help you sift through everything we’ve covered, I’ll quickly sum up each power supply’s strengths and weaknesses.

  • Ahanix SilenX 400W – Ahanix wasn’t a name that I’d commonly associated with power supplies before this comparison, so I didn’t quite know what to expect from the SilenX 400W. With a weaker maximum 3.3V wattage than the competition and the highest system temperatures of the lot, I almost wrote off the SilenX. However, it was the quietest power supply in our isolated noise tests, which makes me think it could be perfect for silent PC projects. The SilenX also has tight DC voltages with low ripple content, so power quality isn’t an issue at all. Unfortunately, the SilenX line doesn’t seem to be widely available. I could only find a couple of retailers selling the 400W model for $99, which seems a little high considering unit’s 400W rating, plain appearance, and lack of extra features.

  • Antec TrueControl 550W – The TrueControl 550W takes everything that we liked about the TruePower last year and rolls it up with voltage and fan speed control. Honestly, there’s not much not to like about this power supply, though I do have some reservations about how easy it will be to tweak the 3.3, 5, and 12V lines accurately without expensive equipment to verify the actual voltage on each line. The TrueControl is the loudest power supply in this comparison with its fans cranked all the way up, but that high fan speed setting also kept our system running the coolest, which bodes well for overclockers. Those concerned with noise can always turn down the fan speeds and make the TrueControl much quieter. A price tag of $110 might scare less dedicated enthusiasts away from the TrueControl 550W, and that’s probably a good thing. Newbies shouldn’t be messing around with voltage levels, and they probably won’t need adjustable fan speeds. However, those features are all there for finicky tweakers who demand flexibility.

  • Enermax EG651P-VE(FMA) 550W – At $126, the EG651P-VE(FMA) 550W is the most expensive power supply in this comparison, but the unit’s dual sheathed cables, glossy finish, adjustable fan speed, and relatively low ripple voltage nicely justify its higher cost. The EG651P-VE(FMA) also offers more 12V wattage than any other power supply in this comparison, and it cools well without making too much noise. For what it offers, it’s hard to call the EG651P-VE(FMA) 550W overpriced, but it’s definitely overkill for even most enthusiasts. Against its most direct competitor, Antec’s TrueControl 550W, the EG651P-VE(FMA)’s lack of voltage adjustment won’t score points with the hard-core tweaking crowd. However, the power supply’s shiny finish and extra sheathed cable will make case modders swoon, and the massive 12V maximum output wattage could turn even Tim Allen into a computer geek.

  • Vantec Ion 400W – Because of its relatively low noise levels and higher system temperatures, the Ion 400W is wedged somewhere between the dual- and single-fan power supplies. Unfortunately, the Ion has the most ripple of any of the power supplies we looked at, and not by a little. The Ion’s saving grace may be its relatively low $64 price tag, which is about $30 less than the next cheapest power supply in this comparison. You get what you pay for. With less ripple content and a slightly higher voltage on the 12V line, the Ion 400W could have been the darling of this comparison. In the end, it still looks like a capable power supply for those looking for a cheap option with a couple of extra features that generic power supplies tend to lack.

  • Zalman ZM400A-APF 400W – The stealthy ZM400A-APF was full of surprises in my testing, and that’s a good thing. First, the ZM400A-APF delivered the tightest DC voltage tolerances of the bunch, with relatively low ripple content to boot. The ZM400A-APF also managed lower system temperatures than the other single-fan power supplies in this comparison, albeit while making a little more noise. In the end, it’s the ZM400A-APF’s comparably high $92 price tag and low 12V maximum wattage that sours me on an otherwise capable power supply. It feels like Zalman could have gone a lot farther with the black aesthetic to really cater to modding enthusiasts, too.

  • Antec TruePower 550W – The winner of last year’s comparison, Antec’s TruePower 550W turned in an impressive performance, but it’s ultimately made obsolete by the TrueControl 550W. The TrueControl and TruePower 550W are both available online for roughly the same price, but the TrueControl delivers voltage and fan speed tweaking features along with all the TruePower’s sexy dedicated output circuitry.

Personally, I lean towards Antec’s TrueControl 550W, because I’m not a stickler for looks. I’m also probably one of a small percentage of enthusiasts who would actually take the time to properly calibrate voltage lines to perfection. I could be the only one who considers dedicated output circuitry sexy, too, so I realize that the TrueControl has far from universal appeal. In the end, none of the power supplies we looked at today is right for everyone, but using the performance and feature analysis we’ve provided, you should be able to find one that fits your needs.

Comments closed
    • Anonymous
    • 16 years ago

    I didn’t read any other comments yet.. but I noticed the author didn’t realize what the connector on the back of the Antec Truecontrol was for.. it is there so you can stick the leads of a digital multimeter into them to properly adjust the voltage levels without having to open up the case. As to Its black connectors.. in the world of connectors, black connector housings denote a higher-temperature plastic and will stand up against melting better than regular nylon connector housings. Melting is always a non-issue in the PC world, as the curent levels are low enough.. so basically Antec is just using a higher quality connector than everybody else. It seems the industry has chosen black connectors for SATA, but for purely aesthetic reasons.

    • Anonymous
    • 16 years ago


    • Anonymous
    • 16 years ago

    This review was like 99% of all the power supply reviews found on the web, including the recent one by Anandtech. It was technically incompetent and was grossly inadequate because no amp measurements were made to verify that the supplies could deliver their promised performance.

    #78: The power figures on the first page are based on manufacturers’ specifications, not actual measurements, and most readers are interested in real-life performance.

    • Anonymous
    • 16 years ago

    #85: That’s what I needed to know! Now I can update my spreadsheet. Thanks! #84

    • Anonymous
    • 16 years ago

    Thanks XSasber for #80 From #61: I’ve built a fancy spreadsheet to calculate a system’s power demands, but I don’t know which rail to assign the CPU power to. AMD’s pdf sez it should be 12V. Anandtech’s questionable article keeps implying high 3.3V current benefits AMD users. Do you happen to know which rail is used for the on-board switching CPU power supply is on the ECS mobo?

      • Anonymous
      • 16 years ago

      #84, Athlon power is derived from either the 5V rail or 12V, depending on the motherboard manufacturer’s choice of design. When the motherboard has the “Intel/P4” 4-pin connector, the board uses 12V for CPU. When the board lacks this connector, it uses 5V, PERIOD. I know it’s a lot easier to believe some PDF or website, but the PDF is only a “suggestion”.

      Since you have been receiving contradictory info, there’s only one way to resolve this, hands-on. Take a voltage meter and measure voltage on the high-side FET. There is no mistaking this reading, it is PROOF enough.

      As for your ECS board, I have it’s predecessor, the K7S5A, and would suggest that the power supply isn’t the limitation so much as the motherboard, that ultimately you “get what you pay for” with a board as well as a power supply.

      That ECS board uses 5V for CPU. An economical power supply would be a top name-brand in a 300-350W range, depending on other factors, additional load from devices such as the video card. Since your board doesn’t use 12V for CPU, a more economical power supply can be used, it need not have the exceptionally high 12V capacity only seen by using a >=400W model.

        • Anonymous
        • 16 years ago

        I’ve seen a lot of misinformation here and in the review…

        First off, Antec doesn’t make power supplies, nor does Zalman. They both RELABEL existing power supplies that are minimally modified from original design IF they make reasonable requests. If you like whatever cosmetic eye-candy they choose to add and feel like paying a “middleman”, resulting in higher price for attributes not-so-directly related to performance, then by all means pay their higher prices. The price markup “can” be worthwhile if they substitute a fan that’s preferred for noise issues and the user would rather keep their warranty intact than break the seal, open the unit and swap the fan themselves (or for users not inclined or able to safely do so).

        Second, I’m a little amazed that the Zalman and Ahanix weren’t recognized as identical (or very nearly so)… They’re both the same power supply with very minimal change. Almost as incredible is that neither was properly identified as a relabeled Sparkle/Fortron power supply. I can only conclude that while the reviewer has done some prerequisite reading, that MUCH hands-on experience is needed before undertaking the next power supply review. It’s not a bad review, but to be a competent power supply review the reviewer really needs both an EE degree and years of computer hardware experience, including a high variety of contemporary power supply designs… after all, we’re judging how good and bad they are relative to other available choices, right?

        Also in the review it wasn’t nearly stressed enough that the labeled capacities are a CLAIM, not evidence, and certainly not trustworthy. For instance, it’ll be a cold day in he!! before the Enermax can deliver it’s rated output. It’s spec’d for MTBF at 70% load unlike many PSU’s 100% load MTBF rating. That’s implying that the Enermax is really only worth 70% of it’s labeled capacity… ALL of the power supplies can deliver a brief peak output, but most better power supplies don’t claim that figure is the capacity. If you take that 70% figure and mutiply by the total rated wattage, you’ll know better which other power supplies to compare them to, and then realize that it’s just a really well-dressed, well-marketed, overpriced option unless the system needs a visual makeover more than a power upgrade.

        More than anything this review indicates that the Vantec was a notch below the rest. It’s not low-end, but about the same value/dollar as the others, so you do get what you pay for.

        Unfortunately there was one detail sorely lacking in the review, though it’s lacking in most reviews, which is the internal temperature of the power supply. Take ANY/EVERY power supply, use a quieter fan or more aggressive noise-throttling design to lower fan RPM, and you reduce airflow, increase heat. What would be useful is to know which power supply stays cooler inside at the user’s choice of noise… it’s not a big deal to swap in a different fan if you don’t mind voiding the warranty, but it’s important to know beforehand, how much of that noise is due to a fan grill or internal components butted-up against the fans and the venting, and how much is instead simply due to moving more air (of course ignoring the minor differences in efficiency between the different makes).

        Also a very very important issue completely ignored is fan type and brand. A top name-brand dual ball-bearing fan is a MUST for any modern medium to high-end system. The power supply becomes most efficient near max capacity, slightly lower efficiency below that. It’ll be generating near 30% of the system’s total heat and drawing pre-heated air into itself for it’s own cooling. It’s just silly to risk complete failure of the power supply by buying a unit with a generic lower-quality fan even if it is ball-bearing.

        Finally, high-frequency noise emission onto the main AC should be considered, as well as self-preservation/safety… some power supplies don’t even have surge protection inside. I’ll bet all of these do, but there’s no way to be sure without seeing good, hi-res pictures of the insides. That’s one of the biggest problems with this review, that it’s lacking these hi-res pictures. Opening the units would’ve also allowed a more easy comparison between the Ahanix and Zalman models tested, and if you accumulate these pictures you often identify manufacturer of the unit even when it’s labeling or exterior looks quite different.

    • XSaaber
    • 16 years ago

    That would depend on your definition of what is considered reliable is. By your choice of motherboard I would assume that you are trying to keep the cost down to a minimum so you might be looking at something in the 1500+ to 1900+ range for a CPU. If you are using the memory from the motherboard you are replacing, such as PC133 a faster CPU won’t make a big difference because your memory bus is the bottleneck. The type of video card you use can be a deciding factor as well, the newer ones require much more current on the 12v and 5v rails. Since you work on a lot of different systems you may have to do some experimenting with faster CPUs to find out for yourself.

    • Anonymous
    • 16 years ago

    To the anon complaining about the amps not being listed – open your eyes and look at the table on the first page.

    also just use P/V=I if you must use the wattage – however this will not hold up quite correctly for the enermax 3.3/5 rails as they are shared.

    Who needs big 5v anyway, surely it is the 12v rail that gets hammered now adays with the fans/hdds and processor demands? The enermax would have got my vote since the 12v rail supply outstrips the others. It would be nice to load up a few resistors to the supplies and see the ripple produced then.

    • Anonymous
    • 16 years ago

    Chill on the Grills –

    Counting grill openings on the power supply is pretty meaningless – much of it depends on the skill of the designer in handling airflow. It may actually be better at cooling if there was but one intake fan and one outflow fan with /[

    • Anonymous
    • 16 years ago

    About the only thing good about that review was that you guys measured the voltage output on each rail. But even at that, it’s still suspect since no specs were given as to the type of digital scope you used.

    I’m sorry… but seriously, if you’re going to test power supplies, there’s gonna have to be more work done by you guys than what you did. AG #39 and AG #60 pretty much said it all.

    I wanna see how the PS handles power sags… I wanna see a constant load test and a progressive linear load test done.

    And please let your readers know what’s the most important number they need to look at… AMPS!! Screw watts… I wanna know how many amps the 5V+ and 12V+ rails can handle. Watts mean jack if the PS can convert effiecently and handle loads.

    • Anonymous
    • 16 years ago

    Another vote for “please include a cheap/generic PSU in the next review”.

    Being able to dial in the voltages on the Antec TrueControl, I was very surprised to see that the unit wasn’t tested with its voltages appropriately adjusted. If it was, this fact wasn’t made clear in the review.

    Thanks for the effort, I enjoyed the review.

    • XSaaber
    • 16 years ago

    I think Geoff did a good job on the review. The SilentX looks like a good PS for those that want a quite PC, but you will need an additional case fan to cool your enclosure. I have used several Antecs and they are good as well, though I did have one motherboard that had boot problems with the Antecs but had no problems with PC Power and Cooling supplies. I am not saying that the Antecs were out of spec but some chipsets are sensitive to the timing issues, such as how long it takes for the voltage rails to turn on, in what order they come on, and how quickly they ramp. The Zalman and the Vantec are a bit of a mystery to me with their low 12v current rating. With the newer motherboards, CPUs, the increased amount of memory, and the way manufacturers of motherboards use 12v it is a critical element along with the 5v.

    • Anonymous
    • 16 years ago

    I couldn’t get my Antec to work with Ati AIW 9700pro and Nforce2 ultra 400 board.

    Service quy tried two cards and two boards from different makers, but no go. Different Antec models didn’t help either (it was tried with 380W and 480W TruePowers, I think).

    Fans would just spin a little when powering on, and then the system would stop.

    I had to change to a cheaper power supply (which kind of invalidates the point of the article 😉

    The system had no problems with a regular 9700pro nor other cards I threw at it.

    Clearly the newer 9800pro works, since it is used in one of the test systems.. And AIW seems to work in KT400 based board.. Sigh..

      • nismo
      • 16 years ago

      same thing happened to me… after I got a new revision 9700AIW, when the fan on the first one died. Had to go with a 9800, luckily for less money than the refund.

    • ieya
    • 16 years ago

    Am amazed at how poor US petrol seems to be – even regular pump stuff here is 95 octane, and Shell’s Optimax, which I use, is more like 98.

    • Mr Bill
    • 16 years ago

    “…I could be the only one who considers dedicated output circuitry sexy…” Well, you and Bender.

    Interesting that most deviations sag to negative. I guess because no temporary (millisecond scale) storage like one would get with a battery or a large transformer. I’d suggest that a rsd measurement to go with each voltage measurement would be informative. Nice read, I liked it.

    • Anonymous
    • 16 years ago

    I’m still looking for a power supply article that addresses typical system power requirements and stability. Anybody (with a alot of $$) can buy a powerful supply and install any processor. But I work on lots of systems that needs a cpu/mobo upgrade and don’t want to add in an expensive power supply. I need to know what the max freq processor can be installed for a given supply wattage or current/rail. Example: I’ve got a 300W Compusa power supply with 14A of 3.3V, 20A of 5.0V power and 12A of 12V. What’s the fastest AMD processor I can install on a ECS K7S5A Pro with good reliability. Assume a basic system configuration since we are talking about upgrades on a shoestring.

      • Anonymous
      • 16 years ago

      well a 12a 12v rail will be eaten up in no time

      a hdd takes 2a on full, a dvd/cdrw about 1.1a on full, a 2000+xp about 7.5a on full so already you are looking at a regular 1hdd/cdrw/dvd/2000xp using close to 12amps.

      get a bigger PSU

    • Anonymous
    • 16 years ago

    You need to simulate load at or close to mfr’s claimed ratings before you have an ide of how good a supply is. This is easily done using high wattage resistors of the correct value (which is calculated with Ohm’s law). Also as another poster said, how does the power supply cope with transients?

    All your article showed is performance at some (unknown) rating. This is meaningful only if I have a similar system to you – but even if I did there is no reason to think that a 550W supply is any better than a 400W supply based on your article. If you had shown that a 550W supply achieved low ripple and cool operating temperatures at 550W load while the 400W supplies got hot and couldn’t produce clean power at 400W load then that would have been something useful. If you had loaded up a system with components to see if you could make the weaker supplies sag and then compared the performance of the higher-rated supplies that might have been useful too.

    It’s a real shame when kids write hardware reviews without knowing what they’re doing. The lemmings rush out and buy TEH WINNAR and mfr’s decide not to bother supporting the enthusiast community with review samples because the results are pure bullshit – why should they give out free samples when the results are a crap shoot?

    • Anonymous
    • 16 years ago

    I hardly think the TruePower 550 can be called obsolete just because there is a new model with (literally) knobs on. Don’t forget, not everyone looking for a high-spec power supply is doing so in order to support overclocking projects of dubious utility and merit. The original niche for this type of PSU (and the most important one, by any objective measure) is high-end multiprocessor-laden RAID servers, and the most important features for that purpose are the current capacity per rail and the stability of the DC voltages. Standard 3.3V, 5V and 12V (or close enough within standard tolerances) will do just fine, thank you.

    • Anonymous
    • 16 years ago

    #53 again…the vantecs -5 and -12v rails seem to be listed in reverse as the two table contradict each other.

    • Anonymous
    • 16 years ago

    Slight mistake on the first page…. the enermax with 36A on all its rails delivers 480w on thr 5v rail but a mere 432w on the 12v rail, and having a combined 3.3/5v score of 200w? errr…might wanna try 180 instead.

    And consequently, it doesnt offer the highest wattage on every rail from the units on test, its actually got the lowest 5v rail.

      • Dissonance
      • 16 years ago

      Fixed the 480, it should be 180. The combined 3.3 and 5V is 200W, though.

        • Anonymous
        • 16 years ago

        Oh i know its only meant to be 200 – i was pointing it out cos it highlighted the 480 for me in the first place….thought it was kinda silly to have 480 on one rail but max 200 from both ;D

    • Dissonance
    • 16 years ago

    To everyone asking about PC Power and Cooling power supplies: I emailed them several times asking if they wanted to participate in the comparison, but didn’t get a response to any of my emails.

    • bobo007
    • 16 years ago

    Discraceful ! shame !
    How could you exclude the PC Power and Cooling supplies?
    The specs alone blow all the supplies you tested out of the water.
    How and you recomend a supply running at +/- 3 to 5 % ?
    I am sure they have value, but in my book +/- 1% is better than +/- 5%.

    • AmishRakeFight
    • 16 years ago

    Great review, and I agree that if you are an enthusiast, a high end power supply is a great investment. However I’ve built hundreds of systems using generic power supplies for joe sixpack and I’ve had fewer power supply related issues than I’ve had with faulty ram or motherboards in 7 years of system building.

    and my BMW runs great on regular unleaded 😀

    • Krogoth
    • 16 years ago

    My Turbolink 420W PSU is handling my system well even when I overclocked the system a little bit from 2083 Mhz to 2200 Mhz with a ASUS A7N8X 1.4 Rev.
    Which can’t handle 200 FSB at rock-hard stability but, I managed to get it to POST,boot-up and benchmark with it
    The Turbolink PSU handles my load of 2 Optical drives, 2 ATA100 HDs, 4 Case Fans, and a Radeon 9700 fairly well and manages to be fairly quiet.
    I could however go with a brand-name PSU just to be safe but, I the problem to what to do with the Turbolink PSU. My case is only two that are full-towers right now at my places and the rest of computers are mid-towers you know the wiring mess a 420 PSU can do interior of a mid-tower case anyways.
    The Turbolink PSU must of cost $40 which isn’t bad nor cheapo the case I get cost $80 which can with the PSU

      • Anonymous
      • 16 years ago

      I really can’t stand people who can’t figure out how to express their views and just keep typing and typing and have no clue as to what punctuation is used for it makes it very hard for other people to read it it isn’t sensible it makes the person come across as a child it means you’re not worth the trouble to try to decipher what’s being attempted you should grow up and buy a grammar book.

      I can’t even screw up like that when I’m trying.

    • Anonymous
    • 16 years ago

    So what’s wrong with the amount of ripple/noise shown by that one PS? For all we know, ten times that amount would be within spec and no reason to base a buying decision upon.

      • Anonymous
      • 16 years ago

      Because fundamentally, undervoltages and noise on supply lines are bad for an electronic system.

      There a few simple facts about electronic systems:
      1) Wacko glitches will happen. Anything can cause them – anything at all, with cosmic rays being a large portion of the failures as well.
      2) When a wacko glitch happens, how the system behaves is going to be dependent on how close to its ‘baseline’ it is.
      3) Just because something is ‘within spec’ doesn’t mean that it’s ideal. Most electronic parts are specced within commercial temp range ( 0 – 70 deg C). That doesn’t mean they’ll work WELL over that temperature range – buffers will slow down, power consumption will vary, etc. Anytime you vary from a “nominal” and start eating into your “acceptable range”, you’re reducing noise margin and increasing susceptibility to problems.

    • Anonymous
    • 16 years ago

    I REALLY like the idea of a molex output on the back, I’d use that to test equipment w/o opening my rig (we don’t all have space for a test bench)

    BTW: When you’re saying 90mm fan in the article are you referring to the standard 92mm models or a unique 90mm fan?

    • Anonymous
    • 16 years ago

    your review was mediocre at best.

    It would have been better if you had done some line impairment testing,
    looking at how the supplies dealt with dips, brownouts, and sags, lost
    cycles, off freq., etc.

    It would have been even better to look at how the supplies dealt with
    major changes in load like when a P4 wakes up from it’s deep slumber
    and goes to full active in a matter of a few clock cycles time or what
    the +12V line looks like if you spin up an array of 4 IDE disks all at once.

    How efficient are these supplies?

    How much hash do they put back onto the AC line (conducted emissions)?

      • My Johnson
      • 16 years ago

      I wouldn’t rate the review mediocre though. I thought the conclusion was done well and there were still many helpful benches. But I can’t help but concur that a few more benches would be welcome. Some may require a big investment in time and money though.

    • Anonymous
    • 16 years ago

    theres a reason why power supplies are the most neglected components…!

    • Anonymous
    • 16 years ago

    The PC POWER AND COOLING 510 series, kicks all these guys arses.
    You get what you pay for

    • Anonymous
    • 16 years ago

    Come on, try out a SuperMicro 400W, those suckers are sweet (all my systems have one, quiet and powerful.

    • Anonymous
    • 16 years ago

    Geoff is quite right…a lot of people do buy systems based on high end parts and then get a really cheap power supply to go with it and then wonder why they have problems. It’s amazing that someone would cheap out on the power supply when it is not the most expensive item either. Another thing I see people not spending much money on is a tower case. A tower case with poor cooling was probably fine up until a couple of years ago, but I know my main system would be condemned to lock-up Hell if I didn’t have a good case with decent cooling.

    I agree with post #26, it would be a great idea to throw in a cheap no-name power supply (or two) into the mix for comparison sake. Also it would be a good idea to do a small reliability test of the power supplies for a few days to see if weird problems like computers resetting by themselves happens.

    • Anonymous
    • 16 years ago


    Good review: just a few comments. Yah, some of these might seem too hard to do, but honestly, if you’ve got access to a decent ‘scope and multimeter, this can’t be that difficult. 🙂

    Could you possibly include the RMS noise level from the AC ripple as well (i.e. the average)? That’d give something a little more quantitative, though averaging/stdev/RMS aren’t wonderfully sensitive to outliers, which is one thing you do want to show here. The other point is how tight is the ground loop on the scope probe (i.e. how long are the scope leads?) You may be picking up a fair amount of ambient noise in the ground loop (though in certain cases like the Ion I really doubt it…)

    Final comment is that would it be possible in the future to grab, say, a high current variable resistor (also known as a decent size metal or ceramic rod with sliding tabs that you can connect to 🙂 ) and, without a computer connected (obviously wouldn’t want to risk one!) see how close to the current ratings each one of these power supplies gets?

    The main reason I suggest this is that a lot of times several people choose power supplies based on maximum current on certain rails (because CPUs and various peripherals say they’re going to consume that much). The problem is that you have no idea how well they’re going to supply that maximum current, or even what their definition of “maximum current” is! Yah, it may say 30A, but what it doesn’t say is that “well, the voltage starts sagging at 25A, and by 30 it’s down to about 3.0V”.

    I mean, fundamentally, the voltages HAVE to sag as the current gets near the maximum – it’s going to crowbar. The problem is that you don’t know where that’s going to happen significantly, and unfortunately it looks like from the idle/heavy load test, all of these power supplies can supply all the current your test setup needs, probably with some head room.

    It doesn’t seem too hard – high-current variable resistor, multimeter, and a piece of wire to turn on the ATX manually. Easy ’nuff.

    • Anonymous
    • 16 years ago

    Infinite persistance.

    I would have liked to see the AC ripple measurements done with infinite persistance. It would provide an overall view of the worst case ripple under both load and idle conditions…

    • WaltC
    • 16 years ago

    I would like to have seen a PC Power & Cooling unit included the test. I’ve often wondered whether it’s difficult to obtain one of these for testing, or whether reviewers simply forget about these psu’s as they rarely appear in psu roundups. As much as PCP&C brags about its psu’s in relation to others, it seems they’d jump at a chance to have them compared. But maybe not.

    I have a PC Power & Cooling Turbocool 450 ATX, but use it as a standby these days, backing up an Antec TP 430. I prefer the Antec for two reasons: it works with my UPS and the 450 ATX does not (PCP&C’s active pfc circuitry gets in the way of the UPS–I got directions from the company for an internal solder mod I can make to correct this–but I’m too lazy); and the single fan on the Turbocool is easily louder than both fans on the TP430. Cosmetically, the TC450 is as spartan as they come–doesn’t even offer a sheathed ATX connector for the $189 price I paid–but does come with a 5-year warranty. Still, I could buy two TP 430’s for what I paid for a single TC450 from PCP&C.

    But…one thing I’ve noticed missing from most psu reviews, when they quote the manufacturer’s specs relating to rail wattage and amperage, is the operating temperature the manufacturer lists as the basis for the maximum theoretical specs. As far as I know, PCP&C is the only manufacturer to list its maximum specs at normal operating temps inside the psu. Everybody else either lists them at 0 degrees C, or ~25C, which is at best about (25C) ~1/2 the actual operating temp of the psu in normal use. The actual wattages per rail can easily be 33% less than the manufacturer’s spec at normal operating temps, therefore. This is almost never commented on in psu reviews.

    Basically, right now I’ll own either an Antec TP/TC or else a PCP&C psu, and nothing else, for the simple reason that these are the only two psu’s I know of which completely separate the voltage rails. As this review rightly points out, but fails to emphasize sufficiently IMO, voltage sharing between psu rails is one of the chief causes of general system instability.

    A quick comment about noise levels. Decibel measurement tells only part of the story, of course. What also has to be considered are the frequencies and character of the sounds being generated. For instance, which would be easiest on the ears–listening to a waterfall/fountain at 50 decibels or chalk screeching on a blackboard at 50 decibels? Some fans “whine”–others don’t, etc.

    Last, I’m not a big fan of heavy venting in the rear of two-fan psus designed as currently sold. The bottom intake fan is actually the “vent” and since it intakes air and blows it up into the guts of the psu where the the exhaust fan removes it from the case, if the back of the psu is heavily vented then some of that hotter air from the intake fan will inevitably be recycled back into the case through the rear venting. IE, a psu with a heavily perforated rear vent panel makes a lot of sense with the standard single-fan ATX design, but can actually be counterproductive with the kinds of two-fan designs now available, IMO, at least as far as case temps go.

    Last last, there’s no reason or requirement for voltages to be “dead on” in a psu. As long as the readouts are within the spec tolerance, the hardware is designed to function optimally in the tolerance zones–as optimally as it would function with “dead on” voltages, IMO. It should never be forgotten, as well, that motherboard voltage regulation circuitry is no less important than the psu’s own internal voltage regulation. If this needs adjustment it can often be done right through the bios of most current motherboards (ram & AGP voltage, etc.) without any need for adjusting the psu itself. I’ve seen many problems relating to older motherboards with inadequate voltage regulation for newer hardware in which people mistakenly believe that replacing the psu is the solution. Sometimes it may be but often the best solution there is replacing the older motherboard (or both)…;)

    Didn’t mean to ramble on here, but I enjoyed this psu review and agree with its conclusions, and just wanted to make a couple of suggestions…

      • Anonymous
      • 16 years ago

      Depends how “off” it is. The problem is that lower voltage means higher current (not linearly, though, these aren’t resistors) and reduced noise margin. 3.25 vs. 3.3 is not really huge: 3.20 vs. 3.30V is a fair difference.

      Plus you’re not taking into account the AC ripple as well: if you’ve got that Ion, if it was producing 3.20 V like the EG651P, with that 100 mV ripple, it’ll dip down as low as 3.10V, and probably more than that. As the power supply ages, it’ll probably get worse, too.

      Honestly, the power supplies are better off being slightly overvoltaged than undervoltaged (for obvious reasons: if they’re undervoltaged, they’re getting ‘closer’ to their logical opposite: if their overvoltaged, it’s the other way around). There’s no requirement to be dead-on for things to work, no, but they do work in worse environments that way.

        • WaltC
        • 16 years ago

        Very good points…especially about ripple and how aging can affect a psu.

        I had a situation once awhile back that brought the issue of motherboard voltage regulation to my attention. I had replaced only the motherboard in a system I was configuring leaving everything else unchanged, including the psu. I encountered some severe problems with the new mboard that I shouldn’t have been having and which were unusual. After spending too much time doing routine troubleshooting I decided to look at the power levels–and saw that the voltages were much different than they had been with the other board (way too low–I had to use the bios to increase the cpu voltage a lot before the actual voltage supplied was sufficient to even boot.) My first thought was that the psu was finished, but not having a spare psu at the time, and as I couldn’t rule out the motherboard, I put the old mboard back in–and everything was fine. Power levels were where they should have been. I went out and swapped the mboard for another just like it–wham, same problem exactly. (You can imagine how happy I was by this time.) Changed mboard companies next time and everything went smoothly. I don’t know but imagine I must have stumbled on a bad lot of these boards by that company (Abit), but the issue sure brought the importance of motherboard voltage regulation into focus for me, unfortunately…;)

      • Anonymous
      • 16 years ago

      I heard the PFC circuitry-UPS problem for the first time. Is it specific to the PCP&C supplies only? Can you explain it a bit further?

        • WaltC
        • 16 years ago

        Sure. At home for my personal system I use a CyberPower 1250 AVR ups. The active pfc circuitry in the TurboCool 450 ATX psu allows it to automatically detect what kind of current is being fed into the psu–220v or 110v–and to automatically adjust to the proper voltage standard. What this allows PC Power & Cooling to do is to eliminate the voltage selection switch on the back of the psu, and internalize the switching. What happens is that the pfc circuit in the psu interferes with my ups so that when the wall power shuts off, the ups delays just long enough to break the circuit–and when the wall power goes my box goes down into a reboot–and of course that’s defeating the purpose of the ups.

        The Antec, having the more “primitive” manual switch instead of the active PFC, keeps my box up and running like it should be when the wall power is lost. I’ve got to have that protection, just no two ways about it.

        I wrote PCP&C an email about it some months ago and they responded almost immediately with a very nice message instructing me how to solder a simple connection inside the psu to effectively “freeze” the power standard for 110v N. America (which would have been fine with me.) They identified the problem as an incompatability with their pfc circuitry and the sine waves required by some ups’s. I have no idea the extent to which this is a problem for them, but imagine there must be a few ups’s with the same problem as I notice that now they have a link on their psu product page going to a discussion about using their psu’s with ups’s and covering this information (I would imagine–I’ve never looked as I corresponded with them about this prior to the link being placed on their website.)

        I was frankly disappointed because the schematic I printed off of their website on fixing this problem looked a bit like it was describing a simple jumper which I could bridge internally to defeat the pfc (as I personally have no need of it but do need my ups.) Opening up the psu revealed only contact points that needed to be bridged with wire and soldered. Didn’t have any wire, and was fresh out of solder, but I did have the Antec on hand….

        Yes, this was and is a major product flaw with their designs, IMO. Of course, if you have a ups which works with their PFC circuit it won’t matter, but for the $189 I would have preferred a voltage switch–or at the least an easily accessible jumper to bridge in the event I didn’t need the “advantages” of PFC. I think PCP&C makes a great psu, but the devil is in the details and I think they need some thinking along those lines to better justify their pricing.

      • nismo
      • 16 years ago

      If I hadn’t just gotten a TrueControl550, I would spring for that Turbo-Cool 510 deluxe. It makes me drool just looking at it. All the wiring is sleeved and there are enough molex connectors to choke a donkey.

    • Lordneo
    • 16 years ago

    I’d also like to see power supplies that arent name brand,
    i wonder how many of the reviewed power supplies are actually made by them.. and not rebranded… and without facts, probably most
    Antec, and Enermax are the only 2 that i know are made by them.
    I’ll stick to my Sparkle’s and cheap Powmax’s
    I dont need no stinking fan controls on my PS.

      • My Johnson
      • 16 years ago

      My sparkles are loud as hell. No idea about the quality. The 400 watter also pumps out a ton of heat. case exhaust fans blow cool air.

      The sparkles were purchased pre-2000

      • wesley96
      • 16 years ago

      As for the case of Zalman, they designed the thing (i.e. not a rebadge of some other product – they have PSU designers in the lab), but the production of the units are done elsewhere since they’re primarily a heatsink manufacturer. I’m quite satisfied they’ve hired some competent peeps down there, so I guess that means I can hold onto this Zalman 400W unit I got under the hood.

      • Lordneo
      • 16 years ago

      people have different levels of loudness,
      my 2 raptors w/ bay coolers make more noise then my 2 – 400watt sparkles, (using on/off switch to power second PS for hardware)
      in my dual tower.
      as for heat… well all PS generate heat ,mine are about in between the highs and lows in teh reviews.
      Never had a sparkle fail yet in 10 years.
      my first one was a 200watt At PS, back in 1993.

    • droopy1592
    • 16 years ago

    q[< I'VE SAID IT before and I'll say it again<]q For some reason I thought you were going to say "Read my lips! No new taxes!"

    • Anonymous
    • 16 years ago

    The external molex connector on the Truecontrol 550 can be used for many things. External fans for external radiators come to mind. You could also use it for external PSU switches (IE water pumps) if needed.

    Would be a nice option to have for the ‘just in case’ situations.. though I wouldn’t pay extra just for that feature..

    • JustAnEngineer
    • 16 years ago

    q[<]§ q[

      • droopy1592
      • 16 years ago

      Reduced gas mileage and less power will result, not just because of the more unstable gas (lower octane is more unstable) but because of the EFI system has knock sensors that will adjust ignition to less than optimum when using crappy gas.

      That USAtoday article is BS. I’ve tested that theory, and while on most cars it is true because ignition is adjusted for 86 gas anyway, high performance cars will lose horsepower and mileage, especially turbocharged ones. Octane makes it harder to burn the gas which makes it more stable. That way you can have the ignition fire at the last possible and most optimum point.

      On dyno day at a car party earlier this year, the theory had been tested, and a stock 1.8turbo engined car (audi and vw) got 157 HP with 93octane while getting 144HP on 87 to the ground.

      I can tell you that a long trip to chicago, I got 380miles on a tank before my fuel light came on with 87 (14.5 gallon tank) but with premium I get more like 420 miles on a tank. It does matter.

      I think the point is that the cheap power supplies have less performance, even if your computer can run on them.

        • jae
        • 16 years ago

        Talk about going off on a tangent… 😉

          • droopy1592
          • 16 years ago

          That’s ok.

        • getbornagain
        • 16 years ago

        well yes, i well agree with my eagle talon 2.0 turbo it’ll get 25-27 vs. 21-23 w/ the good stuff and seem a bit more peppy but is it worth the price?

        though i usually run mid grade and call it good enough 🙂

      • indeego
      • 16 years ago

      Look at the flip side. A regular car, say a honda civic or a F Taurus (eek), will see no benefit to higher grade gasoline, period, and they still get you from point A to B maybe a few seconds after a porche, cheaper, and have a lower TCO! Obeying the speed laws, assumingg{.}g

    • eckslax
    • 16 years ago

    Good review. However, there is one suggestion that I would like to throw out. Next time there is a PSU roundup, maybe you could throw in a cheapo generic PSU just to show the gerbils how much of a difference there is between the crappy and quality PSUs. This review was great, but at the same time there was no real low quality unit to compare it to. It bugs the heck out of me when my friends are suckered into buying a case with a generic PSU that claims extremely high wattages but the unit itself is probably worth $10-$20. Then they wonder why their system is unstable.

      • My Johnson
      • 16 years ago

      Yeah, a baseline would help. I’m really curious how the well the real cheapo’s stack up now.

    • Hoser
    • 16 years ago

    The only thing I would have added to the tests would have been to run 2 P4 systems and see how the extra 12v connector stood up against some heavy loads. I would like to know if the psu I buy is really going to be able to take a beating for the overclocking you can do to a P4 2.6C.

      • My Johnson
      • 16 years ago

      Do Athlon mainboards utilize the 12v rail for the board’s power circuitry? I notice the new boards have the connector but I have two I’m using now that don’t use it.

    • atryus28
    • 16 years ago

    The decibel ratings seem way off to me. I have a tornado fan in one of my systems that’s rated at 54 Decibels and I highly doubt your PSU’s are anywhere near that volume. It’s so far away from quiet it’s not funny. If it didn’t make such a difference in tempature I would get rid of it. But with the fans running in my room in the summer it’s not so bad.

    • Anonymous
    • 16 years ago

    I love all my Antec True Power PSUs.

    I hate Deer.

    • indeego
    • 16 years ago

    Wish you could measure reliability over performance, actually. Who’s to say these can handle sags/dips that a UPS might even throw at it? I don’t care about voltage control, temperature, I care about 5+ years of good, reliable use, and quietness.

    Also, I’ve always wondered this, why don’t power supplies come with very small batteries built into them, so if the power does go out, they can at least attempt to power down a system safely, or give the option to do so?
    Go ‘n patent it, if it’s not already been doneg{<.<}g

    • dalamar70
    • 16 years ago

    Wow, 400-550W… I remember not too long ago walking into a nearby computer parts shop and asking for a 300W PS. The guy looked at me and said “what are you doing, running a server?”

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