The latest PC component to undergo a power-efficiency makeover is one we weren’t quite expecting: the hard drive. Western Digital’s latest Caviar SE16 features IntelliSeek, a just-in-time approach to actuator movement that is supposed to not only lower power consumption but also reduce noise levels by minimizing seek-induced vibration. WD claims these gains are accomplished without slowing seek times, which bodes well for the Caviar’s appeal among enthusiasts who demand that power savings not come at the expense of performance.
Western Digital has also given the drive a much-needed capacity boost up to 750GB courtesy of four perpendicular-packed platters, and they’ve fiddled with the internals to improve reliability. Are those changes, coupled with IntelliSeek, enough to elevate the Caviar above its rivals? Read on to find out.
The latest Caviar’s 750GB capacity is a 50% boost for Western Digital, whose drives have topped out at 500GB for some time now. However, the Caviar is far from the first drive to break the 500GB barrier. Hitachi’s terabyte Deskstar is finally starting to pop up at online retailers, and Seagate has offered 750GB flavors of its Barracuda 7200.10 for more than a year now.
At first glance, Western Digital’s stab at the 750GB mark closely follows Seagate’s lead. The 750GB Barracuda 7200.10 achieved its then-industry-leading capacity using four 188GB platters and perpendicular recording technology, and this latest Caviar SE16 does the same. Both drives also feature 16MB of cache and 7,200-RPM spindle speeds. That’s where the similarities end, or at least where they become difficult to compare. Hard drive manufacturers can’t seem to agree on a collection of consistent specifications to publish, so we’re left comparing the 750GB Caviar SE16—model number WD7500AAKS—to its 500GB predecessor, the WD5000KS.
|Maximum external transfer rate||300MB/s||300MB/s|
|Buffer to disk transfer rate||972Mbps||748Mbps|
|Read seek time||8.9ms||8.9ms|
|Write seek time||10.9ms||10.9ms|
|Average rotational latency||4.2ms||4.2ms|
|Idle power consumption||8.40W||8.75W|
|Read/write power consumption||8.77W||9.5W|
|Native Command Queuing||Yes||Yes|
|Warranty length||Three years (OEM)
One year (Retail)
|Three years (OEM)
One year (Retail)
As you can see, the new Caviar doesn’t improve on its predecessor’s 300MB/s Serial ATA interface or spindle speed. Internal transfer rates are much faster for the 750GB drive thanks to the higher areal density of its platters, though. Higher areal densities lead to faster transfer rates by allowing the drive head to access more data over the same physical distance. Western Digital employs perpendicular recording technology to squeeze 188GB onto each of the new Caviar’s four platters, where the 500GB model is stuck with only 125GB per platter using older longitudinal recording tech.
While the 750GB Caviar has a transfer rate advantage over its predecessor, seek times are unchanged. How the drive goes about seek operations is different, though. In traditional hard drives, the actuator rapidly accelerates the drive head to the location of the next data point, regardless of when that data point will actually be in position to access. Because data points are located on a spinning platter, it may take milliseconds—a virtual eternity within the confines of a modern PC—for the target to come ’round. Western Digital takes advantage of this rotational latency with an IntelliSeek mechanism that only moves the actuator as fast as necessary to get it into position for the data point’s next arrival.
IntelliSeek is best thought of as just-in-time actuator movement. The drive head will always move fast enough to be in position to access the next data point, but if that point isn’t due for a few milliseconds, the actuator will take its time getting there. Western Digital says this approach conserves power and reduces noise and vibration compared with traditional actuators that mindlessly dart from data point to data point, and they’re adamant that performance isn’t sacrificed. You can see an animated representation of IntelliSeek in action on Western Digital’s website here.
In addition to outfitting the 750GB Caviar with a more intelligent approach to seeking, Western Digital has equipped the drive with a StableTrac motor that secures the shaft at both ends. According to Western Digital, this arrangement helps the drive deal with environmental vibration that could be induced by particularly loud music or the far-too-common practice of putting a subwoofer right next to a PC. The Caviar also borrows a SecurePark mechanism from Western Digital’s mobile group that parks the drive head off the disk when the drive is powered down, during spin-up and, during spin-down. This feature increases the drive’s tolerance of non-operational shock, and Western Digital adds that it can reduce the creation of microparticles during spin-up and spin-down, increasing the reliability of the drive.
Despite its apparently improved reliability, the Caviar SE16 750GB’s warranty coverage is limited to either one or three years, depending on how you buy the drive. Somewhat counter-intuitively, retail drive kits are only covered for a single year, with three years of coverage limited to bare drives. That discrepancy is odd, but since enthusiasts typically buy bare drives, we’re getting the better end of the deal.
However, even a three-year warranty looks a little stingy next to the five years of coverage you get with any of Seagate’s hard drives and with Western Digital’s own enterprise-class products. When asked why it hasn’t expanded its five-year warranty to include desktop products, Western Digital told us the additional cost just isn’t worth it. Bare drives make up a very small percentage of the market, they say, and the additional overhead and bookkeeping costs associated with longer warranty periods is substantial. Western Digital also claims that its drives have very low failure rates between years three and five. Western Digital is working on an enterprise-class version of this latest Caviar, though, and that drive should carry a five-year warranty.
We’ll be comparing the performance of the Caviar SE16 750GB with that of a slew of competitors, including some of the latest and greatest Serial ATA drives from Hitachi, Maxtor, Samsung, Seagate, and Western Digital. These drives differ when it comes to external transfer rates, spindle speeds, cache sizes, platter densities, NCQ support, and capacity, all of which can have an impact on performance. Keep in mind the following differences as we move through our benchmarks:
|Max external transfer rate||Spindle speed||Cache size||Platter size||Capacity||Native Command Queuing?|
|Barracuda 7200.7 NCQ||150MB/s||7,200RPM||8MB||80GB||160GB||Yes|
|Barracuda 7200.9 (160GB)||300MB/s||7,200RPM||8MB||160GB||160GB||Yes|
|Barracuda 7200.9 (500GB)||300MB/s||7,200RPM||16MB||125GB||500GB||Yes|
|Caviar SE16 (500GB)||300MB/s||7,200RPM||16MB||125GB||500GB||Yes|
|Caviar SE16 (750GB)||300MB/s||7,200RPM||16MB||188GB||750GB||Yes|
|Caviar RE2 (500GB)||300MB/s||7,200RPM||16MB||125GB||500GB||Yes|
Note that the 250GB Caviar SE16 and the Raptor WD740GD lack support for Native Command Queuing. The WD740GD does support a form of command queuing known as Tagged Command Queuing (TCQ), but host controller and chipset support for TCQ is pretty thin. Our Intel 955X-based test platform doesn’t support TCQ.
We have test results from several versions of Western Digital’s Caviar SE16 and RE2. To avoid confusion, we’ll be listing their capacities in parenthesis in each of our graphs. You’ll want to pay attention to the 750GB Caviar SE16, which will appear as the Caviar SE16 (750GB).
Since Seagate makes versions of the 7200.7 both with and without NCQ support, the 7200.7 in our tests appears as the “Barracuda 7200.7 NCQ” to clarify that it’s the NCQ version of the drive. The Caviar RE2, Deskstar T7K250, DiamondMax 10 and 11, 7200.8, 7200.9, 7200.10, ES, SpinPoint T, Raptor X, and Raptor WD1500ADFD aren’t explicitly labeled as NCQ drives because they’re not available without NCQ support.
Finally, we should note that our WD1500ADFD has a slightly newer firmware revision than the Raptor X sample we’ve had since February. The drives still share identical internals, but firmware optimizations could give our newer Raptor an edge over the X in some tests.
Our testing methods
All tests were run three times, and their results were averaged, using the following test system.
Thanks to the folks at Newegg for hooking us up with the DiamondMax 11 we used for testing.
We used the following versions of our test applications:
- WorldBench 5.0
- Intel IOMeter v2004.07.30
- Xbit Labs File Copy Test v1.0 beta 13
- TCD Labs HD Tach v3.01
- Far Cry v1.3
- DOOM 3
- Intel iPEAK Storage Performance Toolkit 3.0
The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz 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.
WorldBench overall performance
WorldBench uses scripting to step through a series of tasks in common Windows applications. It then produces an overall score. WorldBench also spits out individual results for its component application tests, allowing us to compare performance in each. We’ll look at the overall score, and then we’ll show individual application results.
The 750GB Caviar gets off to a good start in WorldBench, turning in a performance matched only by Western Digital’s 10K-RPM Raptors. Still, the drive only has a one-point lead over Seagate’s Barracuda 7200.10.
Multimedia editing and encoding
Windows Media Encoder
VideoWave Movie Creator
WorldBench’s multimedia editing and encoding tests tend not to be bound by disk performance, but Premiere does spread out the contenders a little. In that test, the Caviar finishes in second place, just behind the fastest Raptor.
Photoshop doesn’t prefer one hard drive over the others, but ACDSee definitely has a taste for Caviar. The 750GB SE16 bests the Raptors by more than 10 seconds here, and it’s more than 20 seconds ahead of the ‘cuda.
Multitasking and office applications
Mozilla and Windows Media Encoder
The Caviar SE16 750GB doesn’t score any wins in WorldBench’s multitasking and office application tests, but scores are pretty tight all around.
WinZip and Nero both exploit faster drives, and the 750GB Caviar turns in the quickest time in each test. Its margin of victory is particularly impressive in Nero, where the fastest Raptor trails by 17 seconds.
Boot and load times
To test system boot and game level load times, we busted out our trusty stopwatch.
The 750GB Caviar SE16 rips through our load time tests, turning in the quickest times of any 7,200-RPM drive. In fact, the Caviar is the fastest drive overall in our boot time test, and speedy enough for second place overall in Far Cry. 10K-RPM drives dominate the podium in Doom 3, but then they do have a 2,800RPM spindle speed advantageand at best one fifth the capacity of the 750GB Caviar.
File Copy Test
File Copy Test is a pseudo-real-world benchmark that times how long it takes to create, read, and copy files in various test patterns. File copying is tested twice: once with the source and target on the same partition, and once with the target on a separate partition. Scores are presented in MB/s.
Although a hair slower than the SpinPoint T with the Windows test pattern, the 750GB Caviar dominates the remainder of FC-Test’s file creation, er, tests.
The Caviar’s lead extends in dramatic fashion when we switch to read tests. Not even the 10K-RPM Raptors can catch the latest SE16 here, and the 750GB Seagate drives are between 10 and 20MB/s slower with each test pattern.
Copy tests combine read and write applications, and the Caviar SE16 has already excelled with both. It’s no surprise then, that the 750GB Caviar SE16 takes top honors across FC-Test’s file copy tests, with the exception of a straight copy test with the Windows test pattern where it’s just a sliver slower than the Samsung SpinPoint T.
We’ve developed a series of disk-intensive multitasking tests to highlight the impact of command queuing on hard drive performance. You can get the low-down on these iPEAK-based tests here. The mean service time of each drive is reported in milliseconds, with lower values representing better performance.
The Caviar appears adept at disk-intensive multitasking in our first wave of iPEAK workloads. Things start a little slowly for the SE16, which turns in a middle-of-the-road performance with our dual file copy workload. However, through the remaining four workloads, the drive manages to consistently stay in the top three—an impressive result when most of the other drives tend to favor workloads of one type or another.
iPEAK multitasking – con’t
The SE16’s results are more mixed in our second wave of iPEAK workloads. Here, the 750GB Caviar is only among the leaders with test patterns involving Outlook .PST export operations. When we import the same .PST file back into Outlook, the Caviar falls a few places, finishing in the middle of the pack in one instance. The horror!
IOMeter – Transaction rate
IOMeter presents a good test case for command queuing, so the NCQ-less Western Digital Caviar SE16 250GB and Raptor WD740GD should have a slight disadvantage here under higher loads.
IOMeter transaction rates paint an interesting picture, with the 750GB SE16 faring better with the file server, database, and workstation test patterns than it does with the web server test pattern. The web server workload is populated exclusively by read operations, and that puts the Caviar behind Seagate’s old Barracuda 7200.7 and Hitachi’s Deskstar 7K500. Even then, though, it’s way out ahead of the best Seagate, Maxtor, and Samsung have done lately.
Switching to file server, workstation, and database test patterns that actually include write ops moves the 750GB Caviar up the field to join the rest of the Western Digital family. The 750GB drive can’t quite match the transaction throughput of the 500GB SE16 and RE2 when hammered with more than about 16 outstanding I/O requests, but that’s beyond the demands of a typical single-user desktop.
IOMeter – Response time
Our response time graphs are a little difficult to read, but the results play out much like what we saw with IOMeter transaction rates. The SE16 doesn’t fare as well with the read-dominated web server test pattern, but even there its performance is snappier than all but a handful of 7,200-RPM drives. And with the rest of our test patterns, the 750GB Caviar SE16 is bested only by Western Digital’s enterprise-class drives and its 500GB Caviar SE16.
IOMeter – CPU utilization
With the exception of a couple of spikes here and there, none of the drives we’ve tested registers more than 0.5% CPU utilization in IOMeter. The Caviar SE16 750GB’s CPU utilization is lower than most, but we’re talking about minuscule differences here.
We tested HD Tach with the benchmark’s full variable zone size setting.
The 750GB SE16 and Raptor WD1500ADFD lock horns in HD Tach’s sustained transfer rate tests, and each walks away with a victory. Of course, the Raptor has a 10K-RPM spindle speed and one fifth the Caviar’s capacity, so it’s not the most direct competition for the SE16. For that, we have to turn to Seagate’s Barracuda ES and 7200.10, whose sustained transfer rates fall more than 10MB/s short of the Caviar.
Seagate claws back into the picture in HD Tach’s burst speed test, where the 750GB Caviar stumbles to fifth place. Western Digital drives have had slow burst speeds in the past, but this latest 750GB Caviar at least shows improvement over previous models.
IntelliSeek doesn’t appear to slow the 750GB Caviar SE16 in HD Tach’s random access time test. The drive’s seek time matches that of the 500GB SE16 and is just a tenth of a millisecond off Seagate’s 750GB Barracuda 7200.10.
HD Tach’s margin of error in the CPU utilization test is +/- 2%, and all the drives are within that range.
Noise levels were measured with an Extech 407727 Digital Sound Level meter 1″ from the side of the drives at idle and under an HD Tach seek load. Drives were run with the PCB facing up.
Thus far, we haven’t been able to spot a weakness in the 750GB Caviar’s performance, but one finally emerges when we turn our attention to noise levels. At idle, the drive’s hum is a little louder than expected. Two decibels separate the 750GB SE16 from the quietest drives at idle, although the difference is hard to discern from even a few feet away.
Fortunately, the 750GB Caviar bounces back when we start the seek process. A seek load adds less than a decibel to the drive’s noise levels, and that’s enough to propel it into third place.
For our power consumption tests, we measured the voltage drop across a 0.1-ohm resistor placed in line with the 5V and 12V lines connected to each drive. Through the magic of Ohm’s Law, we were able to calculate the power draw from each voltage rail and add them together for the total power draw of the drive.
While the 750GB Caviar can’t match the power draw of drives with significantly less capacity—higher capacities require additional platters, adding weight that the drive motor must work harder to rotate—it easily pulls less juice than Seagate’s 750GB offerings. The Caviar’s advantage over the ‘cuda is particularly prominent under load, where IntelliSeek appears to pay dividends.
7,200-RPM hard drives are usually split between camps that excel at sequential transfers and those that prefer more randomized access patterns. The Caviar SE16 750GB is different, though, because it doesn’t seem to care what you throw at it. In HD Tach and FC-Test, which stretch drives with sustained, sequential transfers, the Caviar easily dominated its competition. And although it didn’t top the podium with the randomized access patterns of our iPEAK and IOMeter tests, the SE16 spent most of its time at the front of the 7,200-RPM field in those tests. Don’t forget the drive’s pack-leading WorldBench performance or its quick boot and load times, either.
If Western Digital’s latest Caviar does have a preference, it seems particularly adept at performing sequential read operations, as our HD Tach and FC-Test results can attest. Interestingly, this blistering sequential read performance appears to come somewhat at the expense of random read performance, since the SE16 doesn’t fare as well in IOMeter’s read-dominated web server test pattern or a couple of our iPEAK workloads that are heavy on read ops.
The 750GB Caviar is also a little less competitive if you look at its idle noise levels, which are slightly higher than we expected. But the drive saves face with low seek noise levels and frugal power consumption, both of which can likely be credited to the drive’s IntelliSeek actuator approach. IntelliSeek doesn’t appear to constrain the Caviar’s seek performance, either, making this new actuator tech particularly impressive.
Western Digital may have taken its time bringing the Caviar SE16 up to 750GB, but the result was worth the wait. Our only real complaint is that we can’t actually find the drive in stock anywhere; even Western Digital’s online store only has it available for pre-order at $249.99. That’s about a $25 premium over 750GB Barracudas that pack two years of additional warranty coverage, but given the SE16’s superior all-around performance and lower seek noise levels and power consumption, we’d rather have Caviar.