The progression of the mechanical hard drive market is fueled not by ever-increasing spindle speeds, but by the availability of higher-density platters. Cramming more bytes onto each physical disk obviously enables greater storage capacities. At the same time, it also facilitates improved performance by allowing the drive head to access more data over shorter physical distances.
Conveniently, at least for comparative purposes, drive makers have settled on similar per-platter capacities over the last few generations. Sure, actual areal densities have varied a little, and each manufacturer has moved up the platter ladder at its own pace, but they’ve largely hit the same rungs. For example, Seagate and Western Digital both had drives with 125, 188, and 250GB platters. They went their separate ways through the 300s, with WD offering 320 and then 334GB while Seagate jumped all the way up to 375GB. However, it looks like the two are in agreement on the next battleground: 500GB.
Western Digital was the first to squeeze 500GB onto a single disk with the Caviar Green 2TB. Of course, the Green is one of those hippie low-power drives that’s most comfortable sitting quietly in the corner, its reflexes hindered by a slower spindle speed and probably more than a few bong hits. That’s just what you want for a closet file server, external enclosure, or home theater PC, but it’s not really fast enough for a performance-oriented desktop.
Seagate’s Barracuda 7200.12 cranked 500GB platters up to a full 7,200 RPM. However, the ‘cuda was only available with up to two platters, capping the total capacity at just one terabyte. The 7200.12 wasn’t the performance revelation many had hoped, either. Comparatively lethargic access times ultimately held back the drive’s performance under more strenuous loads.
Now, it’s Western Digital’s turn to show what it can do with 500GB platters at 7,200 RPM. The company has brought four of those platters to the table in the latest Caviar Black 2TB.
The Black started shipping back in September, and it’s been in and out of stock at online retailers since. As I write this, Tiger Direct does have drives in stock, although it’s only one of a few e-tailers that do. Still, that’s more than can be said for Seagate’s 500GB/platter Barracuda XT 2TB, which was announced last month, but still isn’t available for purchase.
I wouldn’t be surprised if this latest Caviar Black was in high demand. After all, its predecessor, the Caviar Black 1TB, has reigned as the fastest all-around 7,200-RPM hard drive for quite some time now. The terabyte model’s platters have only 334GB each, so the new Black represents a substantial 50% jump in per-platter capacity. And there’s been an even more impressive boost in areal density. WD’s 334GB platters shoehorn 235 gigabits into every square inch, while the new ones boast an areal density of 400 GB/in²an increase of 70%. Obviously, the potential performance implications of such a leap are quite exciting.
|Maximum external transfer rate||300MB/s|
|Maximum sustained data rate||138MB/s|
|Average rotational latency||4.2 ms|
|Spindle speed||7,200 RPM|
|Areal density||400 Gb/in²|
|Idle acoustics||29 dBA|
|Seek acoustics||30-34 dBA|
|Warranty length||Five years|
Speaking of performance expectations, the 1TB Caviar Black is rated for a maximum sustained transfer rate of 106MB/s. The 2TB model’s theoretical sustained peak is 138MB/s, which works out to a 30% advantage, but isn’t anywhere close to the sort of linear increase one might expect. The fact is that data get a lot harder to access when you make them smaller, pack them tighter, and then have them rotate at close to an effective 120 km/h.
To help the new Black hit these smaller moving targets, WD equips the drive with a trick dual-stage actuator mechanism. The first stage uses a traditional actuator that, according to Western Digital, gets you into the right zip code. Stage two uses a piezoelectric motor to drive a second actuator that provides 500 nm of fine-tuning precision, taking the drive head down to the right house. 500 nanometers works out to about five tracks, and any so-called “short” seeks within that range can use the piezoelectric actuator without needing to hit the main one.
The piezoelectric-powered actuator is apparently too small to photograph easily (not to mention sealed within a casing I’m not inclined to tear apart just yet), but it’s illustrated in the diagram below. Circled in yellow is the main actuator, with the secondary stage highlighted in blue.
The piezoelectric actuator is more energy-efficient than the main arm, but because it adds a second motor to the drive, Western Digital says that overall power consumption is probably slightly higher than it would have been with a single-stage design. However, the company also claims this dual-stage approach is faster. For a drive like the Caviar Black, marginally higher power draw is a small price to pay for improved performance.
Western Digital tops off this latest Caviar with 64MB of cache memory, double what’s available on other models in the line. The lower capacity points in the Caviar Black line haven’t been upgraded to the denser platters just yet, either. That migration will happen over time, although it looks like model numbers won’t change, making it difficult for end users tell which drives use which platters. At least with the 2TB drive, you know what you’re getting.
Because the 2TB derivative stacks four platters, Western Digital outfits it with a StableTrac motor that secures the drive shaft at both ends rather than just one. The Black also inherits NoTouch ramp load tech, which moves the drive head right off the disk at idle rather than letting it rest on the outer, unused portion of the platter.
Like other members of the Caviar Black family, the two-terabyte model comes with five years of warranty coverage. Three-year warranties are typical for desktop hard drives, with five years generally reserved for high-end and enterprise-oriented offerings.
Test notes and methods
We’ve assembled a small collection of competitors to square off against the Caviar Black 2TB. The Barracuda 7200.12 and Caviar Black 1TB are the most direct rivals (at least until the Barracuda XT arrives), but we’ve also included low-power Barracuda LP and Caviar Green models that match the new Black’s two-terabyte capacity.
Numerous factors affect hard drive performance, including spindle speed, areal density, cache size, and even total capacity. We’ve summed up the key specifications for each of the drives tested in a handy chart below.
|7,200 RPM||341.5 Gb/in²||500GB||300MB/s||32MB||1TB|
|5,900 RPM||341.5 Gb/in²||500GB||300MB/s||32MB||2TB|
Caviar Black 1TB
|7,200 RPM||235 Gb/in²||334GB||300MB/s||32MB||1TB|
Caviar Black 2TB
|7,200 RPM||400 Gb/in²||
|~5,400 RPM||400 Gb/in²||500GB||300MB/s||32MB||2TB|
Despite the fact that Seagate and Western Digital both have 500GB platters, WD’s disks have a higher areal density. The Caviar Black 2TB is also the only one in the bunch sporting a 64MB cache.
We’re using the same test system as in our Vista SSD round-up, so the results from that article are directly comparable to the scores on the following pages, if you’d like an idea of how the Caviar Black stacks up against the latest solid-state drives. We have a Windows 7-based storage test platform under construction, and you can expects the fruits of that effort soon.
Intel Core 2 Duo E6700 2.66GHz
|System bus||1066MHz (266MHz quad-pumped)|
Intel P45 Express
|South bridge||Intel ICH10R|
OCZ PC2-6400 Platinum Edition at 800MHz
|CAS latency (CL)||
|RAS to CAS delay (tRCD)||4|
|RAS precharge (tRP)||4|
|Cycle time (tRAS)||15|
Realtek ALC889A with 2.24 drivers
Gigabyte GeForce 8600 GT 256MB with ForceWare 185.85 drivers
Western Digital Caviar Black 1TB
Western Digital Caviar Black 2TB
Western Digital Caviar Green 2TB
Seagate Barracuda 7200.12 1TB
Seagate Barracuda LP 2TB
Windows Vista Ultimate x64
|OS updates||Service Pack 2|
Our test system was powered by an OCZ GameXStream power supply unit.
With the exception of our power consumption and noise levels, all tests were run at least three times, with the results averaged. We used the following versions of our test applications:
- WorldBench 6 Beta 2
- Intel IOMeter v2006.07.27
- Xbit Labs File Copy Test v0.3
- HD Tach v3.01
- Far Cry 2 v1.3
- Call of Duty 4 v1.4
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 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.
Just four points separate the fastest drive from the slowest in WorldBench, with the Caviar Black 2TB sharing the lead with Seagate’s Barracuda 7200.12.
Among WorldBench’s multimedia editing and encoding tests, only Photoshop performance really seems to be affected by our choice of hard drive. The two-terabyte Black takes the lead in that test, followed closely by its predecessor and then a Caviar Green.
Scores are very close through WorldBench’s office and multitasking tests.
In the Nero test, the Caviar Black 2TB pulls up a little short of the 7200.12. The new Black is faster than the old model, though.
Boot and load times
To test system boot and game level load times, we busted out our trusty stopwatch.
The Caviar Black comes out on top in two of three load time tests, but its margins of victory doesn’t amount to more than a second. Call of Duty load times are virtually identical across the board.
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. We’ve converted those completion times to MB/s to make the results easier to interpret.
Vista’s intelligent caching schemes make obtaining consistent and repeatable performance results rather difficult with FC-Test. To get reliable results, we had to drop back to an older 0.3 revision of the application and create or own custom test patterns. During our initial testing, we noticed that larger test patterns tended to generate more consistent file creation, read, and copy times. That makes sense, because with 4GB of system memory, our test rig has plenty of free RAM available to be filled by Vista’s caching and pre-fetching mojo.
For our tests, we created custom MP3, video, and program files test patterns weighing in at roughly 10GB each. The MP3 test pattern was created from a chunk of my own archive of ultra-high-quality MP3s, while the video test pattern was built from a mix of video files ranging from 360MB to 1.4GB in size. The program files test pattern was derived from, you guessed it, the contents of our test system’s Program Files directory.
Even with these changes, we noticed obviously erroneous results pop up every so often. Additional test runs were performed to replace those scores.
Given its spindle speed and per-platter capacity, one would expect the Caviar Black to do well hereand it does. WD’s latest two-terabyte offering registers the highest transfer rates across all three test patterns. However, it’s not that far ahead of the 5,900-RPM Barracuda LP, which trumps the Barracuda 7200.12 despite having a sizable spindle speed disadvantage.
The 7200.12 bounces back when we turn our attention to read performance, but it’s not quick enough to catch the Caviar Black. Note the dramatic improvement in performance going from the old 1TB Black to the new model.
With the Caviar Black 2TB dominating the file creation and read tests, it’s no surprise that the WD drive offers the quickest file copy performance, as well. The 7200.12 comes close with our video test pattern, which is made up of a small number of extremely large files, but the Western Digital drive has a bigger lead with the other test patterns.
IOMeter presents a good test case for both seek times and command queuing.
The Caviar Blacks thoroughly outclass their rivals in IOMeter, and the latest 2TB flavor offers a healthy performance boost over the old terabyte model. Three of our four IOMeter test patterns include a mix of read and write operations, but the web server pattern is made up exclusively of reads. The Blacks don’t have quite as big of a lead with the web server pattern, especially at heavier load levels, suggesting that strong random-write performance deserves much of the credit for their domination here.
Our peak load of 256 concurrent I/O requests is well outside the norm for PC desktops, but it’s not unreasonable for multi-user or enterprise environments. Hard drive makers often repurpose desktop drives for those markets, keeping the mechanical internals intact while adding a few RAID-specific features along the way. Western Digital’s RE4 is essentially a Caviar Black dressed up for servers, and these IOMeter results certainly bode well for its ability to handle the demanding multi-user loads presented by enterprise applications.
There’s very little difference in IOMeter CPU utilization between these drives. The substantially higher transaction rates offered by the Caviar Black don’t cost much in the way of CPU cycles.
We tested HD Tach with the benchmark’s full variable zone size setting.
Score another oneor make that twofor the Caviar Black. The 2TB drive trumps the competition yet again, this time with a 10MB/s lead over the Barracuda 7200.12.
In addition to offering double the cache of its predecessor, the 2TB Caviar Black’s embedded memory is a little quicker, bursting 12MB/s faster than the terabyte model. The Seagate drives are a little slower in this test, managing only 215MB/s.
Quick random access times have been a hallmark of the Caviar Black line, and the 2TB variant doesn’t disappoint. Its advantage over the 7200.12 may only amount to 2.3 milliseconds, but that’s a virtual lifetime within the multi-GHz confines of a modern PC.
The Caviar Black 2TB’s CPU utilization looks a little high here, but keep in mind that HD Tach’s margin of error for this test is +/- 2%. With that factored in, the Black doesn’t come out looking all that bad.
Noise levels were measured with a TES-52 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.
The terabyte Caviar Black has always been a little on the loud side, and this new 2TB model is no different. Generally speaking, the more platters a drive has, the louder it is, making the four-platter 2TB drive’s higher noise levels no surprise. The Barracuda 7200.12 is so quiet at least in part because it only has two platters. What about the four-platter Barracuda LP and Caviar Green? They’re low-power drives with slower spindle speedsa perfect recipe for lower noise levels.
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. We were able to calculate the power draw from each voltage rail and add them together for the total power draw of the drive. Drives were tested while idling and under an IOMeter load consisting of 256 outstanding I/O requests using the workstation access pattern.
Drives with fewer platters also tend to consume less power than those with more, which is why we see the 7200.12 hanging with low-power drives like the Caviar Green and ‘cuda LP in our power consumption tests. The Caviar Black 2TB consumes at most a couple more watts than the terabyte drive, which actually translates to fewer watts per gigabyte.
The Caviar Black line has been a favorite of ours for quite a while now. Some hard drives tend to perform exceptionally well in one or two tasks but comparatively poorly in others. The Blacks have traditionally offered excellent performance in a wide range of applications, from straight-line sequential transfers to real-world file operations to highly-randomized access patterns. They’re jacks of all trades, and better yet, masters of many. This latest Caviar Black 2TB is no different. In fact, it’s the fastest 7,200-RPM hard drive we’ve ever testednot just in one or two benchmarks, but pretty much across the board.
While the new Black’s performance credentials are beyond reproach, the drive does have an obvious weakness: relatively high noise levels, especially when seeking. This characteristic doesn’t come as a surprise given the comparatively high noise levels of the original terabyte Black, which has one fewer platter than this new model. Still, it’s a concern for anyone looking to put together a quiet desktop, especially given Windows’ propensity to perform seek-heavy indexing and optimization in the background.
There’s also the matter of the Caviar Black 2TB’s rather expensive $300 asking price. Price premiums are par for the course with flagship products, though, and this is the only two-terabyte drive you can actually buy today that spins 500GB platters at 7,200 RPM.
Of course, it may not be for long. Seagate has already announced a 7,200-RPM Barracuda XT that pairs a faster 600MB/s Serial ATA interface with four 500GB platters. The Caviar Black 2TB may wear the 7,200-RPM performance crown for now, but there’s already a challenger to the throne waiting in the wingsand in our labs.
If you need to buy a high-performance 2TB drive today, the Caviar Black is obviously the one to get. It’s your only option, after all. However, I can’t wholeheartedly endorse the drive without first seeing how Seagate’s latest stacks up in comparison, which is my next project. One thing is certain, though: the Barracuda XT is going to have to be a huge improvement over the 7200.12 to upset the Caviar Black’s reign.