Now that I’ve opened with a Shameful Car Analogy, let’s move on to computers, specifically to overclocking. The prime enemy of the overclocker is heat. Pumping up the CPU voltage goes hand in hand with the quest for higher clock speeds, but higher voltage means substantially more thermal output from the processor. There are ways to deal with this heat: beefy, all-copper heatsinks with large fans, even water-cooling systems. Of course, the problem here is that the material we’re using to cool the processor, be it air or water, is at best room temperature to start with. What we want is better than “at best”a cooling supercharger. Enter phase-change cooling and the Vapochill.
Phase change 101
The key advantage of the Vapochill system over air cooling or water cooling is its ability to cool the processor below room temperature. It accomplishes this task using phase-change cooling, much like an air conditioner or a refrigerator. For the uninitiated, here’s a primer on phase-change cooling.
First, it will probably help to understand some theory on how gases behave with respect to temperature, pressure and volume. Pressure and volume are inversely related; as pressure goes up, volume goes down, and vice versa. Take a turkey baster or a baby’s aspirator and plug the end with your finger, then squeeze the bulb. As you squeeze, you’re lowering the volume of the container, and at the same time, you can feel the increased pressure on your finger.
Temperature is directly related to pressure; as pressure increases, so does temperature. For example, if you have a volume of gas in a sealed container, and you heat that container, the pressure inside will increase. To look at it from the opposite direction, if you have a certain amount of gas and you compress it, you’re decreasing the volume, thus increasing the pressure and the temperature. If you then reverse the process, you’ll increase the volume, thus decreasing the pressure and the temperature.
Of course, a gas doesn’t have to be a gas. Do things to it, and you can change it into a liquid. For example, if you lower nitrogen gas to -320 degrees Fahrenheit at standard atmospheric pressure, it will condense into a liquid. As you might expect, different gases condense at different temperatures.
Notice that in the example above, I used the caveat “at standard atmospheric pressure.” That’s because the temperature at which a gas will condense varies with regard to pressure; the higher the pressure, the higher the temperature at which condensation will occur.
So let’s review: Assuming a constant volume, temperature goes up as pressure goes up, and temperature goes down as pressure goes down. A gas can be turned into a liquid if it gets cold enough, and the higher the pressure, the “less cold” the gas needs to be in order to condense into a liquid. Such a transition, from gas to liquid or vice versa, is called a phase change.
Now, let’s expand on an earlier example. Suppose we have a gas in a sealed container that enables us to compress the gas within. Suppose also that the container and the gas inside is at room temperature. We compress the gas, decreasing its volume, which raises its temperature as well as its pressure. We could decompress the gas to its original volume, which would restore its original pressure and temperature. But what if, instead, we somehow cooled the compressed gas? Since the higher pressure means the gas will condense at a higher temperature, if we got the right gas, we could theoretically turn it into a liquid by cooling it to at or above room temperature.
Let’s assume that such a gas is present in our sealed container, and we cool that gas down to a point where it condenses into a liquid. Now, we decompress the liquid to its original volume. What happens? Well, the pressure is no longer high enough to keep the gas in its liquid state, so it evaporates, or turns back into a gas. As the volume increases, the pressure decreases, and so does the temperature. Because we cooled the gas while it was still compressed, upon decompression it drops below room temperature. This ability to produce temperatures below ambient is the key advantage of phase-change cooling, whether it’s in your air conditioner, your refrigerator, or the Vapochill system.
How the Vapochill does it
Of course, our example of one large sealed container isn’t very practical for actually cooling anything, so the Vapochill system is necessarily more complicated. It basically consists of four parts: A compressor, a condenser, a throttling or expansion valve, and an evaporator.
As one might expect, the compressor compresses the gas, raising its temperature and pressure. Once compressed, the hot gas flows through metal tubing to the condenser. The condenser looks like a miniature radiator, and it draws heat away from the gas and disperses it outside the system. With an air conditioner, outside the system means outside the house. With a refrigerator or the Vapochill, outside the system basically means “the room it’s sitting in.” Once cooled, the gas condenses into a liquid and makes its way to the throttling valve.
In order for the system to cool effectively, there must be a distinction between the high pressure portion of the system which contains compressed gas and/or liquid, and the low pressure portion of the system, which contains gas waiting to be compressed again. This separation is accomplished by the throttling valve.
The throttling valve is a very small tube called a capillary tube. The high pressure liquid flows into this small tube, and from there to the evaporator. The small diameter of the tube restricts the flow of the liquid, allowing only so much to flow in a given amount of time. This moderates the evaporation process and keeps the high and low-pressure areas separated.
Once the liquid flows through the throttling valve, it goes to the evaporator. The evaporator has a larger volume than the throttling valve, so the liquid immediately undergoes a drop in pressure, evaporates to a gas, and loses a significant amount of heat in the process. The cold gas is in direct contact with the evaporator, so it draws heat away from the evaporator, cooling it.
In an air conditioner or refrigerator, the evaporator looks a lot like the condenser; it is a radiator through which air is blown or drawn. As the air passes through the cold evaporator, it’s cooled, providing the refrigeration effect. With the Vapochill, the evaporator is a copper plate approximately the size of a quarter, which is in direct contact with the CPU core. Thus all of the Vapochill’s cooling potential is concentrated on the core of the CPU.
On a more general note, regardless of the configuration of the evaporator, the cold gas “steals” heat from the evaporator, becoming warm gas in the process. It then flows out of the evaporator and through tubing that takes it back to the compressor to repeat the process.
Let’s check out some pictures of the beast before we look at the installation process.
Here’s a shot of the Vapochill enclosure from the front and the side. Placed next to a Shuttle cube for comparative purposes, the Vapochill looks large and imposing, but in reality it’s about the same size as a typical full-tower case. If you look through the holes at the top of the front bezel, you can see the fins of the condenser. Due south of the right edge of the 5.25″ bays is the LED display for the ChillControl unit. The ChillControl is the circuit board inside the Vapochill that monitors and controls the cooling system. When the Vapochill is powered on, the display shows several pieces of information, including the temperature of the evaporator. Starting at the top right of the case and moving down, you can see the power LED, the hard drive LED, the power switch and the reset switch.
A few particulars on the Vapochill enclosure itself: It will support ATX or eATX motherboards, and there are bays for three 5.25″ drives and six 3.5″ drives (one of those external). There is a mounting location for a 120mm fan to cool the hard drives, as well as mounting locations for up to three 60mm case fans.
If you look at the side picture, you’ll see a seam about two-thirds of the way up on the enclosure. Below the seam is the area of the case reserved for computer components, like the motherboard, drives and power supply. The area above houses the compressor and condenser. The lower portion of the case is accessible via a slide-off panel on each side secured by two thumbscrews. The upper cover is considerably more difficult to remove, but once your system is set up, you’ll have no real need to get into this area anyway.
Once you get the top cover off, this is what you’ll see. The compressor is the big black piece in the middle, and the condenser is the piece on the right with all the copper tubing. The fan attached to the condenser is a large 120mm model that goes about its job very quietly.
Finally we have the CPU kit. This assembly clamps down onto the CPU, allowing the exposed copper evaporator to directly contact the CPU core and keep it substantially cooler than room temperature. Here’s an extreme close-up of the evaporator itself:
Note the outer and inner layers of foam insulation around the evaporator. We’ll talk more about those in the installation section.
Finally, here’s a shot of the included hardware. In case you haven’t guessed, phase-change cooling is a little more complicated than an air-cooled heatsink or even a water-cooling system. Fortunately, Asetek has thought of everything and made sure it’s included. Some of the notable items include a special ATX extension cable to supply power to the ChillControl computer, heaters (!) for both sides of the CPU socket, plenty of insulating foam, and even a serial cable and software for programming the ChillControl board. There’s also a big, fat tube of heatsink paste, which is good, because as you’ll soon see, you’re gonna need it.
Before I get into the installation proper, I’d like to explain why we’ll be doing all the things we’ll be doing. We’ve already talked about how the Vapochill’s big advantage is its ability to cool below room temperature. As it happens, that is also results in a key disadvantage: the potential for condensation. No, not the condensation of refrigerant that occurs in the condenser, but the condensation of water molecules out of the air. Think of a can of Coke, straight out of the fridge, sweating on a coaster.
Keeping condensed water off your coffee table is easy enough, but things get a bit trickier when you’re trying to keep water from condensing around your cold CPU. Imagine if water spontaneously appeared on the back of the motherboard, or under the processor, or even in the holes of the processor socket.
Bad things, man, bad things.
So it’s not enough simply to install the motherboard, screw down the CPU kit, and fire the thing up. Condensation must be prevented from forming, and that is done by filling any empty space in the neighborhood of the CPU with something else. With what, you ask? Why, foam and goo, of course!
Uhh, never mind, you’ll see when we get there.
I should also state for the record that the Vapochill comes with an excellent spiral-bound manual which is broken up into several sections, including separate sections for Socket 478 and Socket 370/A installations. Each of the install sections has twenty-six pages with photographs and diagrams, and they thoroughly document the install process.
The first step is to bend the tubing leading to the CPU kit so that the CPU kit itself is properly aligned with the processor socket. In order to do this, you first have to mount the motherboard. Fortunately, the Vapochill enclosure has a motherboard tray that is only two screws away from popping right out. Asetek supplies plastic clips that push into pre-drilled holes on the tray. After clipping the mobo on to the tray, you’ll have to put the tray back into the enclosure, so you can align the CPU kit. When you’re done, the CPU kit will be in line with the processor while just dangling free, and it’ll look something like this:
So, now that you’ve got the motherboard all nicely mounted in the case, it’s time to… remove the motherboard tray, and then remove the motherboard from the tray. I’m not sure why Asetek has you do the alignment at this point. It seems to me it could be done later on, eliminating the step of installing the motherboard, removing it, then installing it again.
Anyway, now that the motherboard is back off the tray, it’s time to do some reconstructive surgery, starting with removing the heatsink retention bracket from the board. Once bracket is removed, it’s time to break out the Vapochill’s pre-cut pieces of foam. You’ll fit one of these pieces of foam insulation on the bottom of the bracket, so when the bracket is reinstalled, the foam will be sandwiched between the bracket and the motherboard. The foam cutouts are so exact that they even take the ZIF socket lever into account, but they require proper orientation in order to fit. Once the foam is oriented properly, you’ll have to mount the heatsink bracket again.
Then it’s time to break out the goo. Remember the large tube of heatsink paste I told you about? Don’t expect any leftovers.
If you’re worried about smearing this stuff all over your CPU and motherboard, don’t be. The heatsink paste included in the kit is completely non-conductive. However, if you ever decide to switch processors, I’d strongly advise against the use of Arctic Silver for this job. 🙂
You have to apply goo all over the socket, smearing it into the holes (Asetek includes a pipe cleaner) and into the gap at the center of the socket. What you’re doing here is filling up all the empty spaces around the CPU, because any space left empty would leave room for condensation to form. Another piece of pre-cut foam and goes down into the hole in the center of the socket. The final product looks like so:
Here’s a wider shot that shows the foam around the socket as well as the socket itself:
You’ll use more heatsink paste to fill in the center area of the back of the CPU, covering all the transistors. When you’re done, the back of your precious P4 will look like this:
You’ll need to install one of the heating elements from the kit onto the back of the motherboard, like this:
Now it’s time for another piece of foam. This one has adhesive backing like the heater element, and applies directly over the element itself.
Okay, back to the top of the board, where the processor should be nestled comfortably into its goo-filled socket. Another piece of pre-cut foam insulation goes on top of the socket, then the top heating element goes over the foam. You’ll then have to install the Vapochill unit’s retention bars. A picture of the finished product:
With the foam-and-goo stage complete, the motherboard goes back onto the tray, and the tray goes back into the enclosure. The final stage of the installation involves fine tuning the alignment and securing the evaporator assembly using the retetion bars.
The power supply is an optional item on the Vapochill. Our test unit didn’t come with a one. When selecting a power supply, keep in mind that it needs to have enough juice to run not only all the normal system components, but the Vapochill as well.
The Vapochill comes with a special ATX extension cable. One end of the cable connects to the power supply’s ATX plug, while the other end connects to the motherboard. A separate connector block that is part of the extension cable plugs into the ChillControl board to power it and the compressor. There are also separate contingencies for the 4-lead ATX12V connector, but I’ll go over that in more detail later.
You’ll need to connect the two heating elements to the appropriate connectors on the ChillControl and hook up the appropriate motherboard connectors, such as the power switch, reset switch, and power and hard drive LEDs.
Asetek says that the parts used in the installation are typically reusable two or three times. Looking at the procedure, I would expect that just about everything could be reused repeatedly, with the exception of the heating element and adhesive foam that go on the back of the motherboard. The other pieces aren’t adhesive mounted (except the second heating element, but there’s no need to remove it from the foam it’s mounted to) so they should be fine, though you’ll probably need some more heatsink paste if you change motherboards more than once.
If you do need additional install parts, Asetek has you covered. They sell kits that contain only the pieces that might need replacing if you change processors or motherboards. In fact, they even sell kits that enable you to convert your Socket 478 Vapochill system to a Socket A system or vice versa. The kits are pretty reasonably priced: The Socket A version is typically $20-25, and the Socket 478 version is around $40-45. Again, Asetek says you can typically apply and remove the various parts two or three times before having to worry about replacing them, so you almost certainly won’t need one of these kits every time you upgrade your motherboard.
When you finally fire up the Vapochill, you’ll find it does… nothing. Well, that’s not really fair. It definitely powers up. The power light comes on, you can hear a couple of quiet fans and what sounds like a dorm fridge if you listen closely, and there’s a hyphen crawling left to right across the display on the front of the case. But dammit, it won’t POST! Your mind ponders how long you spent putting everything together, and the thought of going over everything to look for mistakes makes you cringe.
Well, fear not; this is all perfectly normal. See, if the Vapochill hasn’t been on for a few days (or, for example, since it was tested by Asetek prior to shipment) it takes several minutes to start cooling the evaporator effectively. If the system were allowed to POST at this point, the CPU would likely overheat before the evaporator started working. Therefore, the ChillControl computer holds the motherboard’s reset line high (the equivalent of holding down the reset button) until the evaporator cools down to -5C. Incidentally, if your system does actually POST when you first turn it on, turn it off and check to make sure the reset line from the case is hooked up correctly. When I assembled everything, I was off by a pin, and going into the BIOS revealed the CPU temperature climbing very high very quickly.
Within five or so minutes, the display on the front of the Vapochill will start counting down from 10. At this point it’s actually displaying the temperature of the evaporator in Celsius. When it hits -5, the system will POST. The display will continue to count down until it reaches the target temperature set in the ChillControl computer; by default this is -15C, or 5F.
If you look closely at the (admittedly bad) picture of the display, you’ll see four indicators down the right side: TMP1, TMP2, RPM and MHZ. These display evaporator temperature, optional temperature sensor, compressor speed, and CPU speed, respectively. I should note here that the CPU speed is actually set manually. The ChillControl computer which drives the display has no way to tell the processor speed in realtime, so this piece of information is as accurate as you program it to be.
To cycle through the settings, simply tap the reset button on the front of the case. Actually resetting the computer requires you to hold the reset button down for a second or more. Don’t worry, the system isn’t at all prone to interpreting a tap of the button as “reset my machine now.” You can also set the display to cycle between the four pieces of information. Incidentally, if an error of some sort occurs, an error code will be shown on the display to help you troubleshoot the problem. The error codes are well documented in the manual.
I mentioned briefly the ability to program the ChillControl computer, so I’ll talk more about that now. The computer circuit board has an RJ12 jack that’s accessible by removing one of the side panels. To use it, attach the included cable and plug the other end into the motherboard’s serial port, then boot with the included floppy. Using a simple, menu-driven interface, you can set a number of parameters.
- Hold temp at: This setting determines the steady-state evaporator temperature. By default it is -15C, but you can set it as low as -30C.
- Start PC at: This setting determines the temperature at which the ChillControl will allow the motherboard to POST. Default is -5C.
- Warning at: An audible alert will occur if the temperature set here is exceeded.
- Shut down at: If this temperature is exceeded, the system will shut down completely.
- Fan1 speed: Speed of the condenser fan, in percentage of full speed.
- Fan2 speed: Speed of the optional case fan, in percentage of full speed.
- Pin heater load: This regulates the amount of power sent to the heaters installed above and below the CPU socket.
- CPU speed: This lets you set the processor speed which will be shown on the front display.
- Temperature output: You can select whether the temperatures shown on the display are in Celsius or Fahrenheit.
- Default view: Determines which display parameter is shown by default when the system first powers up.
The manual also gives instructions on updating the firmware for the ChillControl computer, so it’s possible that Asetek will add functionality to the system as time goes on.
I’m just lucky, I guess, but thanks to a unique set of circumstances in the test hardware I used, I got an education in low-level motherboard behavior. It’s just as well; nothing blew up, and I get to relate this interesting story to you, dear reader.
While hooking up the Vapochill’s power connectors, I followed the manual’s instructions and hooked the ATX12V lead to the appropriate jack on the ChillControl board. Then, I hooked the included ATX12V cable from the ChillControl to the motherboard.
This configuration didn’t work too well. When the evaporator temperature reached the point where the motherboard should get powered on, the power supply kept turning itself off and back on. The manual warns about this situation in a paragraph following the hookup instructions for the ATX12V lead. Here’s a direct quotation:
Using the ATX12V socket on the ChillControl makes some PSU shut down. If this is the case, simply connect the ATX+12V directly to the motherboard instead.
That sounded more or less like what I was experiencing, so I followed the instructions, unplugging the power supply’s ATX12V lead from the ChillControl board and plugging it into the motherboard. Once everything was up and running, however, I encountered some strange, intermittent errors. After being off for a long period of time (several hours or so) the Vapochill would run for several minutes and then generate an error message on the front display, error E041. Powering down the system and turning it back on simply caused an immediate recurrence of the error, but I found that if I just powered the box down and let it sit for a few minutes, it would power up normally.
The manual said that an E041 error indicated a “sensor short cut,” a short-circuit in the evaporator’s temperature sensor. That seemed strange to me, because the error cleared if I just left the system powered off for a few minutes, and short-circuits don’t usually just fix themselves. However, since the error was so sporadic, it was a couple of days before I took the time to do some research on the Asetek forums.
Once I did, I found a variety of messages regarding these E041 errors, and based on those messages, it seemed the errors were related to the motherboard I was using, an Abit IT7-MAX2. The reason the system was registering a short-circuit was that the temperature sensor was hitting its maximum value of 65 degrees Celsius. Additionally, it seems that the processors were, at least in some cases, getting significantly hotter than 65C. I found several reports of people who had burned up one or even multiple CPUs due to this problem.
In the default configuration, the ChillControl computer regulates the ATX12V lead to the motherboard, not applying power until it is ready to release the reset line and boot the system. However, with certain power supplies (including, for example, Antec, but not, for example, Enermax) having the ChillControl regulate the ATX12V lead causes problems. Asetek blames this issue on a vaguely formulated ATX standard, and says that the problem may even come and go on some power supplies depending on the motherboard used. If the problem occurs, the only way to get the system to boot is to connect the ATX12V lead from the power supply directly to the motherboard.
Unfortunately, the IT7-MAX2 apparently does not keep power from the ATX12V lead from getting to the CPU when the reset line is held high. You can see where this is going. In the time it takes the evaporator to get down to operating temperature, the CPU is getting power. With no effective heat dissipation method, it gets hot and gets hot quickly. If you’ve increased the processor’s stock voltage, this makes things even worse. The result: the CPU reaches critically high temperatures before the evaporator can cool it off.
Those familiar with the Pentium 4 will say “But what about the processor’s thermal protection mechanisms?” This is a good point. The Pentium 4 has previously been demonstrated to handle removal of a heatsink during active operation. Why the problem here?
I contacted Intel to get some explanations for this behavior. Turns out the Pentium 4 not only has the thermal throttling that many enthusiasts are aware of, it also has an even more severe action, called THERMTRIP in the CPU datasheets. THERMTRIP is asserted when the processor’s internal temperature sensor indicates a temperature of approximately 135 Celsius, a temperature at which permanent silicon damage may occur. When THERMTRIP is asserted, the processor shuts down all internal clocks in an attempt to reduce its temperature. Additionally, in order to comply with processor requirements, Pentium 4 motherboards must remove core voltage from the processor within 0.5 seconds when THERMTRIP is asserted. Of course, this arrangement is designed to protect the processor during normal operation.
When critical temperatures occur while the reset line is held high, things get complicated, for a couple of reasons. First, B0 stepping processors deassert THERMTRIP when RESET is asserted, which could obviously cause issues with the way the Vapochill keeps the system from powering up. Steppings C0 and later won’t deassert THERMTRIP until the deassertion of the PWRGOOD signal (i.e. a complete power off of the system). However, in reality this doesn’t mean the problem is solved with these later steppings, because it’s likely that the motherboard won’t correctly respond to a THERMTRIP event when the reset line is held high, which is the reason people have ended up with dead processors.
Intel pointed out to me that the reset specifications for the Pentium 4 don’t allow for the reset line to be held high for as long as is typical with the Vapochill’s startup procedure. Since such an operation doesn’t conform to Intel’s specifications, any processor deaths which occur in this situation are basically out of their hands.
Personally, I’m somewhat torn on the importance of this problem. I felt compelled to report on it because I experienced it while working on this review, but at the same time, it is the sort of crazy coincidence one might expect when using technology such as phase-change cooling of a processor. Asetek is working hard to remedy these issues. They have contacted Abit about the problem and are doing their best to get it resolved. In the meantime, I would recommend purchasing an Enermax power supply to go with your Vapochill; they seem to work with the default ATX12V configuration regardless of motherboard. If you already have a power supply and it doesn’t work with the stock ATX12V configuration, buy another one. A new PSU is a lot cheaper than a new 3.06GHz P4.
UPDATE: Asetek now has a beta firmware for their ChillControl unit which does not hold the RESET line high during initial startup. Rather, it uses control of the 12V supply to keep the system from starting, then applies 12V and briefly trips the RESET line (basically pushing the reset button) to start the system at the appropriate time. While this new firmware doesn’t help the above compatibility issues with the IT7-MAX2, it should prevent CPU death. With the RESET line low, the processor should have no problem asserting THERMTRIP should the need arise.
We started out by running benchmarks at a stock speed of 2.8GHz with a 133MHz front-side bus, using a retail Intel heatsink. Once that was done, we shot for the highest overclock possible with the stock heatsink, and wound up with a 151MHz front-side bus using a CPU core voltage of 1.825V. Given the 2.8GHz P4’s multiplier of 21, that works out to 3171MHz. In case you’re wondering, both of the overclocked speeds required locking the PCI bus at 33MHz, which is easily accomplished via a setting in the BIOS of the IT7-MAX2.
However, completing benchmarks does not a stable processor make, and there is no way I would run the CPU at this speed, with this heatsink, in day-to-day use. I encountered some random errors during testing that led me to believe the stability was less than perfect. Moreover, this processor was just running hot. I mean damn hot. I couldn’t hold my finger on the side of the heatsink for more than a second or two
Next up was the Vapochill install, which you’ve already read about. Once that was done, we ran another set of tests at stock speeds, to test a curious statement in the Vapochill manual:
An issue not often realized is that a CPU at low temperatures not only will be able to run at higher clock frequencies. It will also have an increased performance compared to an identical CPU running at the same frequency, but where heat is removed with traditional passive cooling.
An interesting statement, no? We’ll explore it more in the benchmark results. Once the second set of stock testing was done, it was time for the Vapochill overclocking experiments.
Cue evil laugh, bolt of lightning in the background.
So how did we do? Well, not bad. We topped out at a 161MHz front-side bus using a 1.85 core voltage, for a CPU speed of 3381MHz. Personally, I was disappointed, but the top speed had little to do with the Vapochill and more to do with our choice of motherboards. As I mentioned before, we used an Abit IT7-MAX2 for our testing, and it ended up running out of steam before the processor or the Vapochill did.
The problem was voltage. The IT7-MAX2 tops out at 1.85V for the CPU voltage. While this is probably a pretty good limit under normal circumstances (with a traditional heatsink) with the Vapochill you would probably do better with a board that topped out at 1.95 or so. To make matters worse, it seems that the IT7-MAX2 wasn’t really giving its all; when set to 1.85V, the PC Health section of the BIOS indicated 1.79V.
Based on the pattern I saw when determining the maximum stable CPU speed, my belief is that the CPU would’ve gone even faster with more juice. I hope to do a follow-up article and explore things further, either with a different Pentium 4 motherboard or with an Athlon configuration. In the meantime, though, I’d like to point out that the Vapochill had no real trouble maintaining an evaporator temperature of 15 degrees below Celsius, even at 3381MHz with a 1.85V core voltage. I have no doubt the Vapochill could handle a significantly faster/hotter CPU than we presented it with here, and the main reason I’m disappointed is because the core voltage limits kept me from exploring the limits of the CPU. Even with more juice, I seriously doubt I’d really be pushing the Vapochill.
Before moving on, I should point out that we received the Premium Edition of the Vapochill for review. The Premium Edition differs from the Standard Edition only in terms of cooling performance; the Standard Edition can dissipate up to approximately 130 watts of heat energy, while the Premium Edition tops out around 160 watts. You can look at a graph of the performance differences here. The Premium Edition costs approximately $50 more than the Standard Edition.
Our processor testing methods
As ever, we did our best to deliver clean benchmark numbers. Tests were run at least twice, and the results were averaged.
Our test systems were configured like so:
|Processor||Pentium 4 2.8GHz (stock speed)|
|Front-side bus||533MHz (133MHz quad-pumped)|
|North bridge||82845PE MCH|
|South bridge||82801DB ICH4|
|Chipset drivers||Intel Application Accelerator 2.3|
|Memory size||512MB (1 DIMM)|
|Memory type||Corsair XMS3200 PC2700 DDR SDRAM (333MHz)|
|Graphics||ATI Radeon 9700 Pro 128MB (Catalyst 7.81.021218 drivers)|
|Sound||Creative SoundBlaster Live!|
|Storage||Maxtor DiamondMax Plus D740X 7200RPM ATA/100 hard drive|
|OS||Microsoft Windows XP Professional|
|OS updates||Service Pack 1|
Thanks to Corsair for providing us with DDR400 memory for our testing. If you’re looking to tweak out your system to the max and maybe overclock it a little, Corsair’s RAM is definitely worth considering.
The test systems’ Windows desktops were set at 1024×768 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.
We used the following versions of our test applications:
- Cachemem 2.65MMX
- SiSoft Sandra Standard 2003 (2003.1.9.3x)
- ZD Media Content Creation Winstone 2002 1.0.1
- POV-Ray for Windows version 3.5
- Sphinx 3.3
- MadOnion 3DMark 2001 SE Build 330
- Unreal Tournament 2003 demo benchmark
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.
We see no real difference between the two stock configurations, but that’s hardly surprising. Even if the colder temperatures did lead to faster operation, we’re cooling the processor, not the RAM. The higher bus speed resulted in a healthy jump in memory bandwidth when going from 133MHz to 151MHz, and a lesser (but still impressive) gain going from 151MHz to 161MHz. Cachemem tends to paint a more realistic memory bandwidth picture than Sandra, so it’s always interesting to look at the results of both programs.
Though the numbers are different, the trends are basically the same. Once again, there’s no real difference between the stock configurations. The two overclocked configurations, however, both provide a significant boost.
Ah, what a difference an overclocked bus makes. We see an 11ns drop in memory latency going from 133MHz to 151MHz, and another 5ns drop going to 161MHz.
Business Winstone measures performance using typical office applications like word processors and spreadsheets. Not the most demanding software in the world, but we’ll take a look anyway.
These results are about where we’d expect them to be, really. The 18MHz jump of the stock cooling configuration is good for a 2.2 point increase, while an additional 10MHz increase in front-side bus nets 0.9 points. It’s worth noting that the two stock configurations turn in identical scores, which is a mark against Vapochill’s claim of increased performance strictly from lower temperature. Realistically, however, I doubt any of these configurations will disappoint when it comes to running office applications. Content Creation Winstone
A more demanding test suite is Content Creation Winstone, which uses more taxing software like Adobe Photoshop and Premiere.
At this point we see a pattern beginning to emerge, with the stock configurations winding up in a tie. The 151MHz FSB configuration gives an impressive gain, while an increase to 161MHz is even better. POV-Ray 3D rendering
POV-Ray is an advanced ray-tracing package which can produce highly realistic images. It is a good test of floating-point math performance.
The overclocked configuration with the stock cooler manages to shave an impressive 46 seconds off the time of both stock configurations. The additional gain of the Vapochill configuration isn’t as impressive, but it still gets an 18 second improvement.
Here the 151MHz configuration gains over 1000 points in 3DMark, while the 161MHz configuration manages an additional 638 points. The two stock configurations continue their deadlock. Unreal Tournament 2003
The Unreal Tournament results basically mirror the other benchmarks we’ve seen so far: The 151MHz front-side bus configuration takes a large lead over the stock configurations, while the 161MHz front-side bus configuration nets a smaller but still substantial improvement. Speech recognition
Sphinx is a high-quality speech recognition routine that needs the latest computer hardware to run at speeds close to real-time processing. We use two different versions, built with two different compilers, in an attempt to ensure we’re getting the best possible performance.
There are two goals with Sphinx. The first is to run it faster than real time, so real-time speech recognition is possible. The second, more ambitious goal is to run it at about 0.8 times real time, where additional CPU overhead is available for other sorts of processing, enabling Sphinx-driven real-time applications.
All of the tested configurations manage to get below the 1.0 mark, with the 151MHz front-side bus configuration posting scores in the .85 range. Still, only the Vapochill configuration manages to break the 0.8 mark.
The Asetek Vapochill is without a doubt the most impressive cooling solution I’ve ever seen. To use another Shameful Car Analogy, it is the Ferrari of PC cooling. With a price of over $500, the Vapochill is reserved for serious enthusiasts with a significant financial commitment, but its performance is well beyond traditional cooling solutions. How many coolers can keep a 3.38GHz processor at a steady five degrees Fahrenheit? IT7-MAX2 issues aside, I am perhaps most impressed by the quality of Asetek’s implementation of phase-change cooling. There are any number of potential problems with phase-change cooling, including such processor killers as condensation and evaporator startup time. Nonetheless, Asetek has managed to solve nearly all those problems, no matter how complicated the solution. We’re talking about a processor cooler with its own firmware-upgradeable computer. Hardcore.
Those put off by the relatively high cost of the Vapochill should consider it as a long-term investment. The system is adaptable from Socket 370 to Socket A to Socket 478, and I see no reason why Asetek couldn’t develop a Hammer kit as well. Break the cost out over two or three processor upgrades, and it starts looking better and better, especially since it will likely enable you to overclock a $100-150 processor to the performance levels of $500 or $600 chips.
In the end, what the Vapochill gives you is peace of mind, the luxury of never again having to worry about an important aspect of your system, processor cooling. Upgrade the rest of your system to your heart’s content, but two things will remain constant: The Vapochill as your processor cooler, and the temperature of that cooler at a nippy five degrees above zero.