Seagate’s Desktop HDD.15 4TB hard drive reviewed

SSDs have cornered the market for high-performance system drives, relegating their mechanical counterparts to secondary storage. Traditional hard drives are simply too slow to keep up with the flash-based alternatives that have taken the PC industry by storm.

That said, mechanical drives still have an undisputed claim to the mass-storage crown. Flash memory’s blistering performance comes at a price—literally. Even after years of falling flash prices, solid-state storage still costs a lot more per gigabyte than traditional hard drives. Mechanical drives are also available in much higher capacities.

Seagate’s Desktop HDD.15 is a perfect example. This latest addition to the mechanical field squeezes four terabytes into a single 3.5″ case. It’s also eminently affordable. You’ll pay just $190 for the thing, which works out to a nickel per gig. The per-gigabyte cost of even budget SSDs is an order of magnitude higher.

The Desktop HDD.15 is the most affordable 4TB hard drive on the market, which isn’t too surprising. While the competition spins its platters at 7,200 RPM, the HDD.15 has a slower 5,900-RPM spindle speed.

Slower rotational speeds are nothing new on the desktop; low-power “green” drives have employed them for years. We typically see slower spindles used to bring up new platter technologies, and that’s exactly what’s happening here. The Desktop HDD.15 is the first four-disc implementation of Seagate’s terabyte platters.

The platters have an extremely high areal density of 625 Gb/in². Their individual tracks measure 75 nm wide, or about a thousand times narrower than the average human hair. Accessing data on such a small scale is no easy feat, especially given the speeds involved. At 5,900 RPM, the outer edge of the platter is moving at the equivalent of 61 miles an hour. Increasing the rotational speed to 7,200 RPM boosts the outer-edge velocity to 75 MPH. No wonder drive makers usually start new configurations at a slower speed.

Of course, even low-speed hard drives need to be incredibly precise. Because there’s so little room for error, environmental vibration can interfere with normal operation, causing the drive head to drift off-track or dangerously close to the surface of the platter. The Desktop HDD.15 features AccuTrac servo tech to maintain read and write performance in what Seagate describes as “high-touch” environments. An all-in-one system pumping music through built-in speakers is provided as one example of such an environment. The product guide also suggests the HDD.15 is ideal for desktop RAID and NAS applications, both of which entail ambient vibration due to the close proximity of other drives.

OptiCache describes the dual-core storage processor and associated technologies that blanket most members of Seagate’s Desktop HDD family. The ARM-based chip is fabbed on a 40-nm process, and it’s infused with improved caching algorithms that work in conjunction with 64MB of DRAM memory. This is a straight-up mechanical drive, so there’s no NAND involved.

Interface 6Gbps SATA
Spindle speed 5,900 RPM
Cache size 64MB
Platter capacity 1TB
Total capacity 4TB
Average data rate 146MB/s
Max sustained data rate 180MB/s
Idle acoustics 2.3 bels
Operating acoustics 2.8 bels
Idle power 5.0W
Typical operating power 7.5W
Warranty length Two years

The Desktop HDD.15’s slower spindle speed produces lower average and maximum sustained data rates than those of Seagate’s 7,200-RPM offerings. Those drives stack as many as three of the same terabyte platters, and they’re rated for an average speed of 156MB/s and sustained peak of 210MB/s.

The performance of mechanical drives usually hinges on the combination of spindle speed and areal density. However, other factors clearly influence the Desktop HDD.15. The drive spins its platters 18% slower than Seagate’s 7,200-RPM desktop drives, yet its average data rate drops only 6%. The HDD.15’s maximum data rate is 14% lower, which is closer to what we’d expect given the difference in spindle speed.

We’ll examine actual performance in a moment. First, I have an axe to grind. The Desktop HDD.15’s warranty coverage runs out after two years. That doesn’t mean the drive will spontaneously combust when the term expires. However, the relatively short coverage doesn’t inspire confidence in a product that will store four terabytes of precious data. It wasn’t too long ago that all of Seagate’s internal hard drives had five-year warranties.

Ok, so it was about 4.5 years ago—pretty much an eternity in the PC industry. If you want a 4TB drive with a five-year warranty today, you have to spring for the WD Black, which rings in at $300. Speaking of the Black, let’s move on to our comparative performance tests.

Lining up the competition

Before diving into our results, we should introduce a new competitor. We wanted a low-power drive to square off against the Desktop HDD.15, so we scored a WD Red 3TB for comparison. Like the HDD.15, the Red has one terabyte per platter and a relatively slow spindle speed. Its capacity tops out at 3TB, though.

The Red 3TB is basically a RAID-optimized version of the WD Green, which is the original low-power desktop drive. Both have the same 145MB/s transfer rate specification. You can find the Red 3TB selling online for $150, which is $10 more than the equivalent Green model.

In addition to the Red, we have a stack of other mechanical hard drives. The collection includes WD’s Black 4TB along with a couple of older, lower-capacity versions of the Black from back when the family had Caviar in its name. 3TB drives from Hitachi and Seagate are on the menu, as well.

You’ll want to pay particular attention to how the Desktop HDD.15 fares against the Barracuda 3TB. The latter uses the same platters as its 4TB sibling but spins them at a much higher 7,200 RPM.

Interface Cache Spindle
Deskstar 7K3000 3TB
6Gbps 64MB 7,200 RPM 411 Gb/in²
Barracuda 3TB
6Gbps 64MB 7,200 RPM 625 Gb/in²
Desktop HDD.15 4TB
6Gbps 64MB 5,900 RPM 625 Gb/in²
Caviar Black 1TB
6Gbps 64MB 7,200 RPM 400 Gb/in²
Caviar Black 2TB
6Gbps 64MB 7,200 RPM 400 Gb/in²
Black 4TB
6Gbps 64MB 7,200 RPM NA
Red 3TB
6Gbps 64MB 5,400 RPM NA
VelociRaptor VR200M 600GB
6Gbps 32MB 10,000 RPM NA
VelociRaptor 1TB
6Gbps 64MB 10,000 RPM NA

A pair of 10k-RPM VelociRaptors is also in the mix, although they’re not direct rivals to the Desktop HDD.15. The Raptors are, however, two of the fastest mechanical drives around.

While it’s hard to rationalize how a 4TB mechanical hard drive really competes with SSDs that cost at least ten times more per gigabyte and tend to be capped at one eighth the total capacity, the comparison has to be made. Here’s the stack of solid-state drives that will be squaring off against the mechanical field.

  Cache Flash controller NAND
Crucial m4 256GB 256MB Marvell 88SS9174 25nm Micron sync MLC
Intel 335 Series 240GB NA SandForce SF-2281 20nm Intel sync MLC
OCZ Agility 4 256GB 512MB Indilinx Everest 2 25nm Micron async MLC
OCZ Vector 256GB 512MB Indilinx Barefoot 3 25nm Intel sync MLC
Samsung 840 Series 250GB 512MB Samsung MDX 21nm Samsung Toggle TLC
Samsung 840 Pro 256GB 512MB Samsung MDX 21nm Samsung Toggle MLC

These six drives nicely cover some of the more popular controller and NAND combinations for modern SSDs. We have representatives from the high end of the spectrum, the more affordable side, and multiple points in between. All the drives are in the 240-256GB range, and you’ll want to keep those limited capacities in mind. In desktop systems, SSDs are best thought of as complementary to mechanical storage rather than as replacements for it.

If you’re a TR regular already familiar with our storage test system and methods, feel free to skip ahead to the performance results. Apart from minor tweaks to the table below, the rest of this page is copied lazily from previous reviews.

Our test methods

We used the following system configuration for testing:

Processor Intel
Core i5-2500K 3.3GHz
CPU cooler
Thermaltake Frio
Asus P8P67 Deluxe
Bios revision 1850
Platform hub Intel P67
Platform drivers INF update


Memory size 8GB (2
Memory type
Corsair Vengeance DDR3 SDRAM
at 1333MHz
Memory timings 9-9-9-24-1T
Audio Realtek
ALC892 with 2.62 drivers
Asus EAH6670/DIS/1GD5 1GB
with Catalyst 11.7 drivers
Hard drives Crucial m4
256GB with 010G firmware

Intel 335 Series 240GB with 335s firmware

OCZ Agility 4 256GB with 1.5.2 firmware

OCZ Vector 256GB with 10200000 firmware

Samsung 840 Series 250GB with DXT07B0Q firmware

Samsung 840 Pro Series 256GB with DXM04B0Q firmware

Hitachi Deskstar 7K3000 3TB with MKA0A580 firmware

Seagate Barracuda 3TB with CC47 firmware

Seagate Desktop HDD.15 4TB with B660 firmware

WD Caviar Black 1TB with 05.01D05 firmware

WD Caviar Black 2TB with 01.00101 firmware

WD Red 3TB with 80.00A80 firmware

WD VelociRaptor VR200M 600GB with 04.05G04 firmware

WD VelociRaptor 1TB with 04.06A00 firmware

WD Black 4TB with 01.01L01 firmware

Power supply
Corsair Professional Series Gold AX650W
Windows 7 Ultimate x64

Thanks to Asus for providing the systems’ motherboards and graphics cards, Intel for the CPUs, Corsair for the memory and PSUs, Thermaltake for the CPU coolers, and Western Digital for the Caviar Black 1TB system drives.

We used the following versions of our test applications:

Some further notes on our test methods:

  • To ensure consistent and repeatable results, the SSDs were secure-erased before almost every component of our test suite. Some of our tests then put the SSDs into a used state before the workload begins, which better exposes each drive’s long-term performance characteristics. In other tests, like DriveBench and FileBench, we induce a used state before testing. In all cases, the SSDs were in the same state before each test, ensuring an even playing field. The performance of mechanical hard drives is much more consistent between factory fresh and used states, so we skipped wiping the HDDs before each test—mechanical drives take forever to secure erase.

  • We run all our tests at least three times and report the median of the results. We’ve found IOMeter performance can fall off with SSDs after the first couple of runs, so we use five runs for solid-state drives and throw out the first two.

  • Steps have been taken to ensure that Sandy Bridge’s power-saving features don’t taint any of our results. All of the CPU’s low-power states have been disabled, effectively pegging the 2500K at 3.3GHz. Transitioning in and out of different power states can affect the performance of storage benchmarks, especially when dealing with short burst transfers.

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at a 75Hz screen refresh rate. Most of 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.

Noise levels

With SSDs increasingly serving our high-performance storage needs, the acoustic footprint of hard drives has arguably become a more important differentiating factor—especially for PC enthusiasts who have built themselves near-silent systems. We’re a little OCD here at TR, so we’ve constructed a Box ‘o Silence to test the noise emitted by mechanical hard drives. This 18″ x 20″ anechoic chamber is lined with acoustic foam, and we suspend hard drives inside it, exactly 4″ away from the tip of our TES-52 digital sound level meter. You can read more about the setup here.

To ensure the lowest possible ambient noise levels, we swapped the test system’s graphics card for a passively cooled Gigabyte model and unplugged one of the Frio CPU cooler’s dual fans. Noise levels were measured after one minute of idling at the Windows desktop and during an HD Tune seek test.

We’ve color-coded the results by manufacturer to make the graphs easier to read, marking the Desktop HDD.15 4TB with a darker shade of green than the other Seagate drive. Because they have no moving parts and are essentially silent, the SSDs are missing from the noise results. When they do appear in the graphs, the corresponding bars are greyed out to set apart what is really a different class of PC storage.

The Desktop HDD.15 is a little quieter than its 7,200-RPM sibling at idle, but the two make about the same amount of noise when seeking. Seagate’s acoustic specifications put the two drives on relatively equal footing, and our results agree. Any acoustic advantage imparted by the HDD.15’s slower spindle speed is likely nixed by the addition of the fourth platter. We’ve found four-platter drives to be generally louder than their three-platter counterparts.

That said, the Desktop HDD.15 is still a very quiet drive. It registers a couple decibels below the WD Black 4TB at idle and nearly seven decibels lower while seeking. The HDD.15’s seek chatter sounds muffled, especially when compared to that of the Black. Clearly, though, the WD Red is our low-noise leader. The thing barely makes a whisper regardless of whether it’s idling or seeking.

We should note that, even when idling at the Windows desktop, the Desktop HDD.15 vibrates enough to make the suspension cords in our test chamber oscillate with a slight hum. When this happens, the drive starts chirping audibly—perhaps an artifact of AccuSync adjusting for the vibration. Putting a paperback book on top of the drive adds enough weight to tension the cords, dampen the vibration, and eliminate the chirping. Apart from cutting out vibration-induced noise, the book’s presence doesn’t appear to change the HDD.15’s decibel output. We tested the WD Black 4TB with and without the book and found no difference in the readings on our meter.

Power consumption

Power consumption was tested under load with IOMeter’s workstation access pattern chewing through 32 concurrent I/O requests. Idle power consumption was probed one minute after processing Windows 7’s idle tasks on an empty desktop.

Thanks in part to its lower spindle speed, the Desktop HDD.15 consumes relatively little power. Under load, it draws less than half of the wattage pulled by the Black 4TB. The WD Red does consume fewer watts than the HDD.15, but it’s a terabyte behind on the storage front.

HD Tune — Transfer rates

HD Tune lets us look at transfer rates across the extent of the drive, and we’ve plotted the full profiles for the mechanical drives in the line graphs below. The SSDs are fast enough to throw off the scale, so we’ve left them out. You can click the buttons below each of the line graphs to see how the Desktop HDD.15 4TB compares to different classes of competitors.

Despite its spindle speed disadvantage, the Desktop HDD.15 tops the average sequential read speed of the Black 4TB by nearly 10MB/s. The HDD.15’s higher-density platters help to offset the damage done by its slower rotational speed. Those same platters yield an extra 18MB/s when spinning at 7,200 RPM in the Barracuda 3TB.

You have to go further down the standings to find the Red 3TB, which manages only 116MB/s in this test. I suppose that’s not too bad. Hitachi’s 7,200-RPM Deskstar 7K3000 has the same average read rate.

While our fastest mechanical drives come close to equaling the read speed of the slowest SSD, all the other solid-state offerings are well ahead. No wonder SSDs are preferred for performance-sensitive applications.

Switching to HD Tune’s write speed test changes little. The SSDs are still way ahead of the mechanical drives, and the Desktop HDD.15’s relative position in the field is unaltered. The line graphs reveal no hiccups in the HDD.15’s transfer rate profiles.

This next test measures the speed of short “burst” transfers that target the DRAM caches on traditional hard drives.

Although Seagate touts the Desktop HDD.15’s 64MB cache, the drive’s burst performance is relatively weak. The Barracuda 3TB boasts much higher scores in these tests, as do most of the mechanical drives, including the Black 4TB.

SSDs use their DRAM caches differently than hard drives, and some don’t have them at all. That’s probably why the results for the solid-state and mechanical drives are so mixed in these tests.

HD Tune — Random access times

Our next set of HD Tune tests probe random access times with various transfer sizes. We’ll start with a line graph showing all the results for the mechanical drives before moving onto bar charts that cover a couple of key transfer sizes.

Slower spindle speeds translate to slower access times. The Desktop HDD.15’s read access times aren’t egregiously high, since the Seagate drive fares better than the WD Red, but they’re a long way from matching the performance of the Black 4TB. Even the 7,200-RPM Barracuda can’t keep up with the Black.

The SSDs, on the other hand, blow the mechanical drives out of the water. Their advantage narrows in the 1MB test, but it’s still no contest.

Well, this is weird. We’ve seen several hard drives turn in odd scores in HD tune’s 512-byte random write test. However, this is the first time a drive has also posted substantially higher access times in the 4KB and 64KB tests. Only in the 1MB test is the HDD.15 competitive with its peers.

TR FileBench — Real-world copy speeds

Concocted by resident developer Bruno “morphine” Ferreira, FileBench runs through a series of file copy operations using Windows 7’s xcopy command. Using xcopy produces nearly identical copy speeds to dragging and dropping files using the Windows GUI, so our results should be representative of typical real-world performance. We tested using the following five file sets—note the differences in average file sizes and their compressibility. We evaluated the compressibility of each file set by comparing its size before and after being run through 7-Zip’s “ultra” compression scheme.

  Number of files Average file size Total size Compressibility
Movie 6 701MB 4.1GB 0.5%
RAW 101 23.6MB 2.32GB 3.2%
MP3 549 6.48MB 3.47GB 0.5%
TR 26,767 64.6KB 1.7GB 53%
Mozilla 22,696 39.4KB 923MB 91%

The names of most of the file sets are self-explanatory. The Mozilla set is made up of all the files necessary to compile the browser, while the TR set includes years worth of the images, HTML files, and spreadsheets behind my reviews. Those two sets contain much larger numbers of smaller files than the other three. They’re also the most amenable to compression.

The SSDs were tested in a simulated used state that should be representative of their long-term performance. We didn’t simulate a used state with the mechanical drives or hybrids, which tend to offer consistent performance regardless of whether we’ve run our used-state torture test.

The Desktop HDD.15’s copy speeds look pretty decent with the larger files in the movie, MP3, and RAW sets. In those tests, the HDD.15 is within striking distance of the WD Black 4TB. However, the gap between the two widens in the TR and Mozilla tests, which involve much larger numbers of smaller files.

Interestingly, the WD Red copies those smaller files faster than the HDD.15. The Red has slower copy speeds with larger files, though.

Once again, the SSDs dominate the standings. Their advantage isn’t as pronounced when copying smaller files, but it’s positively huge when working with larger ones.

TR DriveBench 1.0 — Disk-intensive multitasking

TR DriveBench allows us to record the individual IO requests associated with a Windows session and then play those results back as fast as possible on different drives. We’ve used this app to create a set of multitasking workloads that combine common desktop tasks with disk-intensive background operations like compiling code, copying files, downloading via BitTorrent, transcoding video, and scanning for viruses. The individual workloads are explained in more detail here.

Below, you’ll find an overall average followed by scores for each of our individual workloads. The overall score is an average of the mean performance score for each multitasking workload.

Surprisingly, the Desktop HDD.15 matches the DriveBench performance of the 7,200-RPM Barracuda. The Black 4TB turns in a much higher score, and even the Red has a slight edge over the Seagate drives. Let’s look at the individual scores that comprise our overall average.

There’s really no silver lining for the Desktop HDD.15; it’s slow across the board. The Red pushes more IOps in every test but the transcoding one, where it ties with the HDD.15 at the back of the pack. The Black 4TB enjoys a comfortable lead over the Seagate drives throughout.

Admittedly, disk-intensive multitasking is a sort of worst-case scenario for mechanical storage. SSDs handle the load with ease, as our performance results illustrate.

TR DriveBench 2.0 — More disk-intensive multitasking

As much as we like DriveBench 1.0’s individual workloads, the traces cover only slices of disk activity. Because we fire the recorded I/Os at the disks as fast as possible, solid-state drives also have no downtime during which to engage background garbage collection or other optimization algorithms. DriveBench 2.0 addresses both of those issues with a much larger trace that spans two weeks of typical desktop activity peppered with multitasking loads similar to those in DriveBench 1.0. We’ve also adjusted our testing methods to give solid-state drives enough idle time to tidy up after themselves. More details on DriveBench 2.0 are available on this page of our last major SSD round-up.

Instead of looking at a raw IOps rate, we’re going to switch gears and explore service times—the amount of time it takes drives to complete an I/O request. We’ll start with an overall mean service time before slicing and dicing the results.

Neither of the Seagate drives performs well in DriveBench 2.0. They both sit at the back of the pack, with the Desktop HDD.15 slightly behind the Barracuda. The ‘cuda turns in the same mean service time as the WD Red, which is much slower than the Black 4TB.

The SSDs are way out in front again. Surprise!

Let’s slice and dice the data with a few more metrics. We’ll start by splitting mean service times between read and write requests.

The Desktop HDD.15 has problems with both reads and writes. With the latter, its mean service time is actually a bit quicker than that of the Barracuda. Both Seagate drives trail the WD Red, and they’re well behind the Black 4TB.

There are millions of I/O requests in this trace, so we can’t easily graph service times to look at the variance. However, our analysis tools do report the standard deviation, which can give us a sense of how much service times vary from the mean.

Interesting. There’s little difference in the variability of service times between the Desktop HDD.15 and Barracuda. The duo’s standard deviation for reads isn’t too far off the marks set by the Black 4TB and the Red 3TB. However, the Seagate drives exhibit a lot more variance in write performance than their mechanical peers.

We can’t easily graph all the service times recorded by DriveBench 2.0, but we can sort them. The graphs below plot the percentage of service times that fall below various thresholds. You can click the buttons below the graphs to see how the Desktop HDD.15 compares to different classes of mechanical and solid-state drives.

Well, there’s your problem right there. And there. And there. Sorry, I’m typing out loud as I click the buttons. Across all the plots, the Desktop HDD.15 has fewer service times under just about every threshold. The exceptions are few and far between, and the bulk of them occur below the 0.1-millisecond mark, which is too quick to really feel.

You may, however, notice extremely long service times that spike above 100 milliseconds. That threshold is over on the far right of the plot, where the drives bunch together and differences are difficult to see. Let’s zoom in on the results and compare the percentages of service times above 100 ms.

While the values are low overall, the Desktop HDD.15’s are the highest for both reads and writes. Keep in mind that the results pertain to nearly two weeks of I/O activity. Even a small percentage adds up to a substantial number of long access times.


Our IOMeter workloads feature a ramping number of concurrent I/O requests. Most desktop systems will only have a few requests in flight at any given time (87% of DriveBench 2.0 requests have a queue depth of four or less). We’ve extended our scaling up to 32 concurrent requests to reach the depth of the Native Command Queuing pipeline associated with the Serial ATA specification. Ramping up the number of requests also gives us a sense of how the drives might perform in more demanding enterprise environments.

There’s too much data to easily show on a single graph for each access pattern, so we’ve once again split the results by drive class. You can compare the Desktop HDD.15’s performance to that of the competition by clicking the buttons below each graph. Note that the scale is different for the Raptor results.

We’ve also banished the SSDs from this set of results. Their transaction rates demand a much higher scale, making it impossible to discern what’s going on with the mechanical drives. You can see how the SSDs compare on this page of our Samsung 840 Pro Series review.

In the read-only web server test, the Desktop HDD.15 scrapes the bottom of the barrel along with the WD Red. Both have lower I/O rates than the 7,200-RPM drives, which are led by a pack of WD Black models. There’s actually a substantial difference between the Blacks and the second tier of 7,200-RPM mechanical drives.

Our IOMeter tests are sensitive to random access times, so slower spindle speeds can be a big handicap. The Raptors illustrate that fact perfectly—just as long as you notice the change in scale on the vertical axis.

The rest of our IOMeter tests mix read and write requests, but the results don’t change appreciably. The Desktop HDD.15 is still outclassed by its 7,200-RPM rivals, and the Raptors are another level above that.

In a fairer fight, the HDD.15 stays one step ahead of the WD Red. The Seagate drive has a slight edge almost throughout, but it stumbles with lighter loads in the file server test.

Boot duration

Before timing a couple of real-world applications, we first have to load the OS. We can measure how long that takes by checking the Windows 7 boot duration using the operating system’s performance-monitoring tools. This is actually the first test in which we’re booting Windows off each drive; up until this point, our testing has been hosted by an OS housed on a separate system drive.

The Desktop HDD.15’s boot time is 1.4 seconds slower than the WD Red’s, 2.2 seconds behind the Barracuda’s, and 2.5 seconds shy of the Black 4TB’s. And the SSDs? They’ll get you into Windows in less than half the time.

Level load times

Again, the Desktop HDD.15 brings up the rear. It’s about as far from the mechanical competition as in our boot test—a few seconds at worst.

The delta between solid-state and mechanical storage is much starker. It’s difficult to tell the difference between the various SSDs, though. Pretty much any halfway-decent SSD will deliver much quicker load times than the best hard drives.

The value perspective

Welcome to our famous value analysis, which adds capacity and pricing to the performance data we’ve explored over the preceding pages. We used Newegg to price all of the drives, and we didn’t take mail-in rebates into account when performing our calculations.

First, we’ll look at the all-important cost per gigabyte, which we’ve obtained using the amount of storage capacity accessible to users in Windows.

Although the Barracuda 3TB is our cost-per-gig champion, the Desktop HDD.15 looks pretty sweet. $180 for 4TB works out to $0.05 per gigabyte. At $300 for the same capacity, the Black 4TB is more expensive than the two-cent difference above suggests.

The SSDs are an order of magnitude more expensive on this value scale. Their actual price tags are in the same range as the high-capacity mechanical drives, though. Our collection of SSDs runs $180-270 online.

Our remaining value calculation uses a single performance score that we’ve derived by comparing how each drive stacks up against a common baseline provided by the Momentus 5400.4, a 2.5″ notebook drive with a painfully slow 5,400-RPM spindle speed. This index uses a subset of our performance data described on this page of our last SSD round-up.

If you’ve been paying attention, this result shouldn’t be unexpected. The Desktop HDD.15 has the lowest overall score of the bunch. Its closest rival is the WD Red, which is also hamstrung by a slow spindle speed. Neither of those two drives comes close to the Black 4TB, which scores higher than all the mechanical models short of the 10k-RPM VelociRaptors.

Now for the real magic. We can plot this overall score on one axis and each drive’s cost per gigabyte on the other to create a scatter plot of performance per dollar per gigabyte. The best place on the plot is the upper-left corner, which combines high performance with a low price.

With the lowest performance and per-gigabyte cost, the Desktop HDD.15 occupies an interesting spot on the plot. It’s very affordable, especially when one considers the total capacity. For the same money, though, the Barracuda and Red are notably faster.

The Black 4TB is a lot faster overall. It also costs close to 50% more, which seems entirely fair given the performance gap. Of course, if you really want something faster, you want an SSD.

The solid-state drives are so much faster—and so much pricier—that they jack up the scale of our plot. There’s no room for labels for the mechanical drives, although it really doesn’t matter. Even without them, the plot nicely illustrates both sides of the expansive gulf between the two prevailing classes of PC storage.


The Desktop HDD.15 is an impressive hard drive. It packs four terabytes for only $190—by far the lowest asking price of any 4TB SATA offering. Seagate reaches that capacity with only four platters, which is a first in the industry. Competing solutions need five platters to match the HDD.15.

Of course, Seagate had to make a trade-off to cram four terabyte platters into a single drive. The company dialed back the spindle speed to 5,900 RPM, putting the HDD.15 at a distinct disadvantage versus typical desktop drives. The 7,200-RPM WD Black 4TB delivers much higher all-around performance. So does Seagate’s own Barracuda 3TB, which spins three of the HDD.15’s platters at the same speed as the Black.

While the results on the preceding pages clearly illustrate the performance gaps between the Desktop HDD.15 and other mechanical hard drives, it seems a little silly to focus on them given the big grey elephant in the, er, graphs. If storage performance is a concern, you should probably be looking at an SSD. These days, hard drives are best left to secondary storage.

In that role, the Desktop HDD.15 is a solid value. If all you’re doing is storing media files, data archives, and Linux ISOs, the HDD.15’s sluggish performance probably won’t be an issue. The drive’s low idle noise level and muted seek chatter will complement a silent SSD nicely, as well. The Desktop HDD.15 isn’t as quiet as WD’s low-power Red 3TB, but it makes less noise than any of the 7,200-RPM drives we’ve tested, including the Black 4TB.

In the end, the Desktop HDD.15 feels like the mini van of PC storage; it provides maximum space with minimum joy. Thankfully, it doesn’t have to be your daily driver. You can park one in the garage next to a small, sporty SSD.

Comments closed
    • kileysmith31
    • 9 years ago
    • willmore
    • 9 years ago

    I’m pretty sure it was around in ’87, but I can’t remember well enough to know how much earlier.

    • Nec_V20
    • 9 years ago


    this would be 1984 or 1985 I was talking about with regard to my 20 MB hard drive, so I am not even aware if the software you are talking about existed. The drive could not find track 0 and the only tools I had available to me were those integrated into the MFM controller.

    Bonn in Germany is a pretty unique place with regard to climate. In fact if you go to your doctor and you see a malaria map then it will have large areas of yellow marking countries around the world where one should get a malaria shot before going there; and if you look VERY closely then there is a minuscule yellow dot in the middle of Germany, and that would be Bonn.

    • willmore
    • 9 years ago

    You should have used a tool like the Gazelle Drive Optimizer which would test different interleaves and then re-low level format the drive a track at a time. I think it became Speedright(?) sometime later.

    • Nec_V20
    • 9 years ago

    Things have come a long way since I was overjoyed to get a 20 MB Seagate 5.25 inch full height hard drive. It had its quirks though.

    I lived in Bonn in Germany at that time and over the years I had it I had to low-level format the drive every Spring and Autumn, when the ambient temperature rose or fell. This meant backing up the drive to 360 KB 5.25 inch floppies every six months (oh the joys of the alcohol I consumed to relieve the boring tedium; MSDOS was not exactly – actually not in the slightest – capable of multitasking and the closest thing to waiting for a 360 KB floppy to be filled can only be compared to the Chinese Water Torture).

    It also had a warning sticker on the top of it to wear safety shoes when handling it.

    Back then, given the pace of PC development I could not even imagine talking about a 1 TB drive in my lifetime let alone a 4 TB one.

    I’ve been a computer techie for 30 years and I still haven’t lost my sense of wonder.

    I recently bought an HDD.15 and I took the review here (among others) into consideration in making my choice. I bought it for the NAS I built and so the speed of the drive is pretty much immaterial considering that the data will be transferred over my gigabit network; making the HDD.15 [b<]exactly as fast[/b<], for my purposes, as the fastest SSD in the comparisons of the review never mind the other hard drives. The prices I had to choose from: Seagate HDD.15 £125 HGST 4TB DeskStar 7K4000 £170 WD 4TB Black £233 This pretty much made choosing the HDD.15 a no-brainer. Another thing I took into consideration which was not even measured in the test above was the temperature of the drives. I assumed that the HDD.15 would run cooler and I was right. I have a Seagate 3 TB 7200 RPM drive in my main machine. I ran the test "h2testw 1.4" for about 15 minutes on both drives. In my two machines the temperatures of the drives were: Seagate 3 TB 7200 RPM drive (ST3000DM001) 44 degrees Celsius (main machine) Seagate 4 TB 5900 RPM drive (ST4000DM000) 33 degrees Celsius (NAS) I doubt that the temperatures on the other 4 TB drives in the test above would be any lower than on my 3 TB 7200 RPM drive. Thus, once again - for my purposes - the HDD.15 comes up as the winner. Both my main machine and the NAS are in well ventilated casings (CoolerMaster HAF X for my main machine and the HAF XM for my NAS) and the ambient temperature in the cases are pretty much the same. So I think that is a pretty fair comparison although the airflow over the hard drives in my main machine is presently better than my NAS (waiting to see if I can get a good deal on a couple of Noctua 120's to fit onto the drive cages). So my own personal review of the HDD.15 - with regard to my own personal needs - in comparison to the other hard drives tested: Performance - exactly equal to the other 4 TB drives tested Price - beats the other 4 TB drives by a country mile. Temperature - runs a LOT cooler than the other drives. Noise - to be honest with my ears I cannot sense any difference between my 3 TB 7200 drive and my 4 TB 5900 drive so call it a draw. As far as warranty is concerned, let's face it every piece of computer hardware is a lottery with regard to when it will fail.

    • l33t-g4m3r
    • 9 years ago

    [quote<]Of course, Seagate had to make a trade-off to cram four terabyte platters into a single drive. The company dialed back the spindle speed to 5,900 RPM, putting the HDD.15 at a distinct disadvantage versus typical desktop drives. The 7,200-RPM WD Black 4TB delivers much higher all-around performance. So does Seagate's own Barracuda 3TB, which spins three of the HDD.15's platters at the same speed as the Black.[/quote<] No, I don't think Seagate had to make a trade off. They already have a 7200 RPM 3 TB drive with the same platters. I'd say this move was more about increasing profit margins, than actual necessity. The decreased speeds is more likely about prolonging the drive's lifespan enough to profitably diminish the returnable failure rate. I'd much rather have a decreased warranty with faster speeds, than the other way around. At the very least, this should be an option. Lowering RPMs here doesn't necessarily inspire confidence in the 3TB drive either. I think it was a bad move to do this, for a lot of reasons. Seagate is basically insinuating their drive quality is terrible, and they're lowering RPMs to compensate.

    • Aliasundercover
    • 9 years ago

    I have one of these in an external USB3 enclosure. When I use it for backups the pace is limited by reading the internal drives. I routinely see 150MB/s writing while read task holds up the parade at 110MB/s on some slightly older 2GB 7200rpm internal drives.

    At 900GB any backup is too long to wait for. Once you go away and let it work on its own even a stately USB2 connected device at 28MB/s doesn’t really matter very much, especially if you can interrupt it and continue later. Software is the key. I do most backups with rsync, yes Linux, which recognizes which files have changed and copies them. I can interrupt it at any time and have it pick up where it left off next time. No doubt there are other similar programs for Windows. If you get the external Seagate they spam you with software like this. Their stuff is annoying compared to the simplicity of rsync but it does work.

    If you are doing image backups, well, why? Is it to restore something obscure and painful to repair like a Windows install? Your best bet would be to keep your Windows system partition small, say 100GB. Yes, not exactly small but big enough all those things Windows just can’t live without having on its system drive are there with room to be sloppy. Then your image backup is 9x faster and your big data can be handled by software which understands what files have actually changed so it is 20x faster.

    Real speed comes from good software but as backup drives go this one is actually very fast. Now if you ask it to do random read heavy work, well, no.

    • sjl
    • 9 years ago

    How fast is fast enough for you? And how much data, total, are you talking about?

    I work as a professional backup/recovery sysadmin. I remember one genius asking me, “Can you backup 22 TB of data?” The correct response is, “Yes. Eventually.”

    900 GB of data over a 6 Gbps interface (the fastest SATA interface, never mind that spinning rusty iron won’t do that much throughput) will take 1200 seconds, or 20 minutes. Factor in the 8b/10b encoding method used, and that increases to 25 minutes. Now consider that the fastest speed a single hard drive, in TR’s tests, has managed is around 200 MB/s, and you’re looking at an absolute minimum of 75 minutes. [b<]Best case[/b<], assuming that everything else is in absolutely perfect working order - personally, I'd be very happy with two hours, and wouldn't be surprised (or concerned) to see it take three or four hours. Or, in other words, "too slow" is a matter of perspective - there's only so much speed you can eke out without spending a fortune on enterprise grade systems, and for the home user, that's massive overkill.

    • Bensam123
    • 9 years ago

    I specifically mentioned caching algorithms as well as well as small files. Caching definitely involves more then just caching small files or simply caching the whole drive. I was pretty sure I covered that in my last post if you read past the first three words though.

    • Bauxite
    • 9 years ago

    Hard Drives, meet ZFS.

    (ZFS waves)

    Carry on.

    • Ushio01
    • 9 years ago

    I have the 3TB Red and also the 1TB Black I kept the Black for my games even though it is loud and now with this review I learn I shouldn’t have bothered as the Red is just as fast. Time to transfer all those games over even though it’s going to take ages “ergh”.

    • Stickmansam
    • 9 years ago

    Torn between getting an 3TB to match my existing 3TB or going for the 4TB and backing up my 1TB as well

    • smilingcrow
    • 9 years ago

    People have been saying that since the days of megabyte HDDs let alone GB or TB drives and the answer is still the same.

    • axeman
    • 9 years ago

    I don’t know why you were downvoted. Not that sudden catatrophic failures don’t happen with mechanical drives, I wouldn’t say they are the majority of it. SSDs are a bit of a different animal, maybe that just comes from too many new players, poor QA, etc, etc. Mechanical storage is very mature industry. Most complete disk failures I deal with are in laptops, where physical abuse is very likely a major cause.

    • willmore
    • 9 years ago

    Both the 3TB Seagate and the 4TB have faster average read and write speeds than the 4TB WD Black, so that might not be a good idea.

    • Walkintarget
    • 9 years ago

    I ended up buying a pair of Seagate 3TBs last year, one for the HTPC and the other in my home server which backs up the HTPC on a nightly basis. Bought them for under $120 each and added a SquareTrade extended warranty for an extra $20 total.

    It’s not as big as the 4TB, and I am no fan of shrinking warranties on HDDs, but I think I did OK for what I use it for. Massive storage (3TBs equals about 500 DVDs) and a backup of all of that content as well.

    • adisor19
    • 9 years ago

    You forgot the 2 year warranty.


    • adisor19
    • 9 years ago

    2 Year warranty. No thanks. Seagate lost my business the moment they dropped their 5 year warranty.


    • dmjifn
    • 9 years ago

    So, if I may ask, what’s the problem with the length of time? Is it because you’re sitting in front of the PC waiting for it to finish? Or it’s tying up some other resource?

    • BIF
    • 9 years ago

    [quote<]Backup your data and quitcherbitchin.[/quote<] There, I fixed it for ya. 😉

    • BIF
    • 9 years ago

    This drive might work well for my backups except that I like my backups to finish quickly. My biggest sample drive partition has about 900+ GB of data. The monthly full backup already takes too a long time in my opinion.

    When the 3 TB drive is no longer big enough to support more than one full backup, I’ll probably go with a Black 4TB…unless 5’s are out by then.

    • Chrispy_
    • 9 years ago

    Yes, much better to store it on four smaller 1TB drives and quadruple your chances of a drive failure!

    [b<]BACKUP YOUR DATA.[/b<]

    • BIF
    • 9 years ago

    [quote<]That is a lot of data to lose at once. [/quote<] There's always one in the bunch. "That won't work" "We shouldn't go that far, we'll fall off the edge of the world" " No computer should ever need more then xkb of memory" Away with you!

    • jihadjoe
    • 9 years ago

    i’d fap to that

    • Waco
    • 9 years ago

    You can’t just cache small files and get good performance. You have to cache small [i<]accesses[/i<]. Just because a file is 64 MB (or hell, 64 GB) doesn't mean you don't access it randomly 4 KB at a time.

    • Thresher
    • 9 years ago

    Better get several of them then…

    • Thresher
    • 9 years ago

    Pretty easy to distinguish, really. Seagate names all their 7200 desktop drives “Barracuda”. This one doesn’t have that name.

    • dmjifn
    • 9 years ago

    Curse you for enticing me to read pages 1 – 11!

    • HisDivineOrder
    • 9 years ago

    The only problem I have with this product is the name and the fact that they do their damnedest to hide the spindle speed, but eagerly let you comparing this product to its similarly named cousins that all feature 7200rpm speeds.

    I get that 4 TB has some speed advantages just in sheer size meaning more data per square inch, but still I wouldn’t say that’s enough to warrant the obfuscation.

    The pricing is mediocre, the drive isn’t as fast or as quiet as other products in similar territory (which I consider any 3 TB drive to be), and so I find it middle of the road in every way. If you absolutely need that extra 1 TB, I guess that’s a selling point, but you’re paying a LOT for that last TB and you’re giving up either greater performance or less noise to get it.

    I’m not sure I find that a spectacular deal.

    • Star Brood
    • 9 years ago

    *Linux iso’s.

    • Bensam123
    • 9 years ago

    Caching small files… Most randomly accessed files are tiny, we’re talking less then 512kb. Mechanicals have issues with lots of small files. It doesn’t need a huge cache to be effective at what it does. The reason they’re still quite a ways away from SSDs isn’t because they aren’t caching EVERYTHING, rather they aren’t caching smartly so lots of things slip through the cracks. The idea of a cache isn’t to cache the entire HD (in that case you’d have a SSD).

    I read the reviews on SSHDs here at TR too, I know how much they have on board. The idea was the drop costs and make it acceptable on all HDs.

    • JustAnEngineer
    • 9 years ago

    Excellent review. You’ve covered a wide range of storage devices here.

    • Krogoth
    • 9 years ago

    4TiB of HD Pr0n……


    • albundy
    • 9 years ago

    might be worth the wait for WD to release their 5TB drive later this year.

    • albundy
    • 9 years ago

    yes, but not instantly like ssd.

    • Peldor
    • 9 years ago

    512MB isn’t enough to provide a SSD-like experience from a hybrid. Most of the hybrids coming out have 8GB or so and there’s still a big difference between them and a regular SSD.

    • Bensam123
    • 9 years ago

    It makes you wonder why they’re picking all these weird RPMs to settle back down to (5900, 5700…). If I remember correctly, 5400 RPMs used to be the standard before they moved to 7200. Is this just to differentiate themselves?

    As I mentioned in the news snippet the other day it makes me wonder when we’re going to move off the 4TB boat, they’ve been around for quite some time now. Hard drive capacities really haven’t increased in years and besides Seagate now getting on the 4TB boat and shaking it up a bit (by lowering the prices drastically) not a whole lot has happened in the mechanical world.

    I’m still hoping we eventually see a complete merger between hybrid SSHDs and normal HDs. This should have an intelligent flash catch to begin with. Even a small one like 512MB just to catch all the little always accessed files would be a step in the right direction. SSHD shouldn’t be a curiosity, they should be the norm. Maybe with a separate model line up of ultra cheap drives that don’t have them. I mean all they really need to work out is the algorithm and then it should simply work with whatever it’s strapped to.

    • ish718
    • 9 years ago

    That is a lot of data to lose at once.

    • odizzido
    • 9 years ago

    I just finished the first page, but yeah seagate does not inspire me with reliability confidence either. I’ve never had good luck with their drives, and when I last updated my comp I got a 500gig seagate drive since they were all sold out of other drives. It has already started clicking like it is going to die, and my older WD ones are still going.

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