Western Digital’s Caviar GP hard drive

Back in the 70s, Kermit the frog lamented that it wasn’t easy being green. My, how times have changed. In this new millennium, being green isn’t only easy, it’s practically expected. Neighbors sneer if you put out more garbage than carefully washed and sorted empties for recycling; grocery stores rake in what I can only assume are huge profits charging five cents per plastic bag; and those who carpool are rewarded with their own special lanes to bypass traffic congestion. Who can blame us, with the inventor of the Internet predicting that melting polar ice caps will one day force us to relive Waterworld.

This push toward environmental friendliness has even permeated the PC industry. Most new components comply with the Restriction of Hazardous Substances (RoHS) directive, for example. The recent trend toward lowering power consumption and improving energy efficiency also lends itself to hugging the planet, even if it was mostly inspired by a desire to reduce the noise generated by Prescott heatsinks.

There’s no ulterior motive behind the latest component to hop on the green bandwagon, though. Western Digital’s new Caviar GP hard drive breaks new ground as the first desktop drive we’ve seen designed explicitly to lower power consumption. Energy efficiency isn’t new in the hard drive world, of course; mobile drives have carefully sipped power to conserve notebook battery life for years. However, the Caviar GP is a 3.5″ drive meant for desktops, and that makes it rather special.

There’s more to the Caviar GP than its Birkenstocks, too. The drive packs a mind-bending 250GB per platter and is available in capacities up to a cool terabyte, making it the biggest drive in the Caviar line. There’s a catch, of course. While most desktop drives spin at either 5,400 or 7,200RPM, the Caviar GP’s spindle speed lies somewhere between the two, and Western Digital won’t say exactly where.

With its spindle speed shrouded in mystery, we couldn’t help but wonder whether the Caviar GP’s performance leans more toward the Tesla Roadster or the Toyota Prius. And what does a slower spindle speed mean for power consumption and noise levels? To find out, we’ve tested the drive against 20 others, with surprising results.

The drive
The fact we don’t know the Caviar GP’s spindle speed is unusual enough, but it only gets more complicated from there. You see, although Western Digital won’t reveal the GreenPower’s exact spindle speed, they did tell us that it varies depending on capacity. The GP is available in capacities of 500GB, 750GB, and 1TB, each of which has a different spindle speed designed to maximize the drive’s overall energy efficiency.

And there’s more.

The GP’s spindle speed falls under an “IntelliPower” umbrella that also includes the drive’s transfer rate and cache size. Western Digital says these three elements are massaged to “deliver significant power savings and solid performance.” Yet spindle speed appears to be the only part of the IntelliPower equation that actually varies depending on drive capacity. GreenPower drives at 500 and 750GB list the same transfer rate and cache size as the 1TB model we’re looking at today.

Differences in spindle speed ensure that Caviar GP performance will depend on capacity. Since we’re testing the terabyte GreenPower, we’ll limit our discussion to that model from here forward.

Squeezing a terabyte into a 3.5″ hard drive form factor is no easy task, but Western Digital has done it in style using platters that offer a much higher areal density than its other drives. The Caviar GP makes use of perpendicular recording techniques similar to those used by the Caviar SE16 and RE2. Those drives only manage to pack 188GB per platter, though, while the GP shoehorns 250GB onto each disk.

Higher density platters can improve performance by allowing the drive head to access more data over shorter physical distances. This effect is evident when we look at the GP’s maximum buffer-to-disk transfer rate, which is nearly 200Mbps faster than that of the Caviar SE16, despite the drive’s sub-7,200-RPM spindle speed.

Although the Caviar GP spins a little slower than its SE16 and RE2 cousins, the drive’s average read seek time is every bit as fast. Don’t get too excited, though. Western Digital doesn’t publish the GP’s write seek time. WD does list the drive’s rotational latency, and it’s quite a bit slower than the RE2 and SE16.

Average rotational latency refers to half the time it takes for a disk to complete one revolution, and with a little simple arithmetic, it’s easy to convert that to revolutions per minute, or RPM. 5.6 milliseconds of rotational latency works out to about 5,400 RPM, which just happens to be the low end of the GreenPower’s spindle speed range. Western Digital says that’s by design; the latency spec it lists in the GreenPower’s data sheets is merely an estimate based on the spindle speed range of the drive. So much for sleuthing.

We’ve been fussing over spindle speeds so much because they play a major role in determining drive performance. But the Caviar GP isn’t meant to ride the bleeding edge of performance; it’s supposed to be quiet and efficient, and the drive’s specs bear that out. Western Digital rates the GP as quieter than either the Caviar SE16 or RE2 at idle and under load. Power consumption is lower, as well. Even with its terabyte capacity, the GreenPower drive requires just four watts at idle—half that of its 750GB cousins. Curiously, though, the GP’s read/write power consumption is actually a little higher than that of the Caviar SE16.

The Caviar SE16 is, of course, a particularly energy-efficient 7,200-RPM drive. Among its power saving features is a little something called IntelliSeek—a just-in-time actuator delivery scheme that conserves power by allowing the drive to move the head only as fast as is needed to get it into position for the next data point. IntelliSeek can also be found inside the Caviar GP alongside a mechanism called IntelliPark. According to Western Digital, IntelliPark unloads idle drive heads to reduce aerodynamic drag, in turn reducing the amount of energy required to spin the platters. The Caviar GP also features WD’s StableTrac motor, which secures the motor shaft at both ends to reduce vibration. StableTrac is only available on 750GB and 1TB GreenPower models, though.

Warranty coverage is consistent across all three Caviar GP capacities at three years. Naturally, we’d prefer to see the GP inherit the five-year warranty lavished upon enterprise-oriented drives like the RE2. That wouldn’t necessarily make the GP more reliable, but it would entitle you to a replacement drive in the event of a hardware failure for an additional two years. Thus far, only Seagate has stepped up to the plate and offered five years of warranty coverage on its standard desktop drives.

Test notes
We’ll be comparing the performance of the Caviar GP 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:

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 parentheses in each of our graphs.

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 other drives 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, 2006. The drives still share identical internals, but firmware optimizations could give our newer Raptor an edge over the X in some tests.

Performance data from such a daunting collection of drives can make our graphs a little hard to read, so I’ve highlighted the Caviar GP 1TB in bright yellow and its high-capacity competitors—the Barracuda 7200.10 and ES, the Deskstar 7K1000, and the Caviar SE16 and RE2 750GB—in pale yellow to set them apart from the others. We also have two sets of IOMeter graphs: one with all the drives, and another with just the Caviar GP and its direct rivals. Most of our analysis will be limited to how the GP compares with its direct rivals, so it should be easy to follow along.

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. Also, thanks to NCIX for getting us the Deskstar 7K1000.

Our test system was powered by OCZ PowerStream power supply units. The PowerStream was one of our Editor’s Choice winners in our last PSU round-up.

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.

Green power gets off to an encouraging start in WorldBench, where it matches the performance of Hitachi’s terabyte Deskstar. The Caviar GP is only one point off the lead here.

Multimedia editing and encoding

MusicMatch Jukebox

Windows Media Encoder

Adobe Premiere

VideoWave Movie Creator

Among WorldBench’s multimedia encoding and editing tests, only Premiere seems to push our hard drives. There, the GP and Deskstar are neck and neck again, just a little off the pace set by Western Digital’s latest Caviar SE16 and RE2.

Image processing

Adobe Photoshop

ACDSee PowerPack

ACDSee benefits more from faster drives than Photoshop, and the GP again finds itself trailing the SE16 and RE2. The GreenPower drive can’t seem to shake Hitachi’s terabyte Deskstar, either.

Multitasking and office applications

Microsoft Office

Mozilla

Mozilla and Windows Media Encoder

None of the drives distinguish themselves through WorldBench’s office and multitasking tests.

Other applications

WinZip

Nero

WinZip and Nero are a little different. In both, the Caviar GP continues its trend of nearly matching the performance of the Deskstar 7K1000. The fastest half of the field is all pretty close in WinZip, though. In Nero, the drives are a little more spread out, with the GP pulling up nearly 50 seconds slower than Western Digital’s fastest 7,200-RPM drive.

Boot and load times
To test system boot and game level load times, we busted out our trusty stopwatch.

Quick boot times are not a strong suit of the Caviar GP. The GreenPower finds itself at the back of the class here, saved from complete humiliation by the Deskstar 7K1000. It’s interesting to note that the terabyte drives turn in the slowest boot times, though.

The GP bounces back in our game load time tests, where it moves up the field a little. However, the Deskstar has a couple of seconds on the Caviar in each test.

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.

To make things easier to read, we’ve busted out our FC-Test results into individual graphs for each test pattern. We’ll tackle file creation performance first.

In this first wave of file creation tests, the GreenPower finds itself trailing the Caviar SE16 and RE2 by hefty margins. The GP does manage to beat the terabyte Deskstar in three of five test patterns, and it’s consistently way ahead of the Barracuda 7200.10 and ES.

Read performance is more mixed for the GP. With the ISO test pattern, which features a small number of large files, the drive falls way behind its rivals and into last place among high-capacity drives. The other test patterns prove more fertile ground for green power, allowing the GP to move ahead of its Barracuda competition. That isn’t enough to catch the Deskstar, though, let alone the Caviar SE16 and RE2.

FC-Test – continued
Next, File Copy Test combines read and write tasks with some, er, copy tests.

The ISO test pattern proves problematic again for the Caviar GP, this time in FC-Test’s copy tests. In fact, the GreenPower drive doesn’t fare that well at all here. It’s slower than the Deskstar 7K1000 in four of five test patterns, and only barely faster in the fifth.

FC-Test’s second wave of copy tests involves copying files from one partition to another on the same drive.

FC-Test’s ISO test pattern proves more manageable for the GreenPower here, but the drive still lags way behind its SE16 and RE2 cousins. At least the GreenPower is able to stay ahead of the Deskstar in most of the test patterns. However, it’s beaten just as often by Barracuda drives that are more than a year and a half old.

iPEAK multitasking
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 GP gets off to a rough start in iPEAK, falling behind its direct competition in our dual file copy workload and well off the pace set by the 7K1000. iPEAK workloads that involve compressed file creation are a little quicker on the Caviar GP, allowing the drive to nudge ahead of the Barracudas. Green power finally hits its stride with workloads that involve compressed file creation, where the GP edges out the terabyte Deskstar. It still can’t catch the latest Caviar SE16 and RE2, though.

iPEAK multitasking – con’t

Our second wave of iPEAK workloads present new challenges to the GreenPower, and we see different trends emerge. Here, the GP performs best with workloads that include a VirtualDub import as a secondary task. Under those loads it’s faster than the Barracudas, but can’t quite catch its other direct rivals. However, the tables turn when that secondary task becomes a file copy operation, plunging the GreenPower into last place among high-capacity drives.

IOMeter – Transaction rate
IOMeter presents a good test case for command queuing. To keep things easy to read, we’ve busted out two sets of graphs here. The first includes the Caviar GP and its closest competitors, while the second has results for all the drives we’ve tested. With over 20 drives, those latter graphs are a little difficult to read, so we’ll focus our attention on the first set and the Deskstar’s direct rivals.

The slower spindle speed doesn’t seem to slow the Caviar GP under IOMeter’s demanding multi-user loads. The drive is consistently faster than its Deskstar and Barracuda adversaries, and its performance scales more aggressively as the number of outstanding I/Os increases. Under heavier loads, the GP is actually faster than the Caviar SE16. In fact, it’s even quicker than the enterprise-oriented RE2 with 128 and 256 concurrent I/O requests.

Good luck with these, folks.

IOMeter – Response time

IOMeter response times look very good for the Caviar GP, making me wonder if Western Digital has an enterprise-oriented version of the drive in the works.

IOMeter – CPU utilization

CPU utilization is low across the board.

HD Tach
We tested HD Tach with the benchmark’s full variable zone size setting.

HD Tach’s synthetic transfer rate tests easily expose the Caviar GP’s greatest weakness: performance with sequential transfers. Even the Barracudas come out well ahead of the GreenPower here, with the Deskstar a good 10MB/s in front.

At least the GP’s burst performance is decent. This is more a measure of disk cache transfer rate, and it looks like Western Digital’s using a similar cache on its latest Caviar and RE2 drives.

Seek performance doesn’t look particularly good on the GreenPower. Despite Western Digital’s claim that the GP offers the same read seek time as its SE16 and RE2, HD Tach’s random access time test clocks the drive at more than a millisecond slower. The Deskstar 7K1000 has just over a two-millisecond advantage here.

CPU utilization results are within HD Tach’s +/- 2% margin of error in this test.

Noise levels
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’ve seen the Caviar GP’s performance suffer due to the drive’s slower spindle speed, but here’s where it all starts to make sense. The GreenPower is the quietest desktop drive we’ve ever tested, by close to a decibel and a half at idle. When seeking, the GP is more than two decibels quieter than the next closest high-capacity drive. What’s more, it’s a whopping six decibels quieter than a Deskstar with equivalent capacity.

Power consumption
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.

The Caviar GP delivers on its energy efficiency promise, too. Even with a terabyte spread over four platters, the drive consumes less power than a single-platter, 160GB Barracuda 7200.9. At idle, you save about three watts over a Deskstar 7K1000. Under a seek load, that advantage grows closer to eight watts, with the Caviar GP pulling half the power of the 7K1000.

Conclusions

Kermit was right: it ain’t easy being green, er, power. Dialing back the Caviar GP’s spindle speed predictably slows the drive, making the GreenPower a poor choice if you’re looking for fast sequential transfer rates, quick load times, or great performance with disk-intensive multitasking loads.

Fortunately, there’s more to the performance picture for the Caviar GP. Western Digital was only aiming for “solid” performance with the drive, and they’ve largely achieved it. The GreenPower performed well in WorldBench, for example, so it’s a perfectly acceptable drive for mainstream desktop applications. Performance in IOMeter was surprisingly good, too, making it tempting to recommend the GP for power-efficient enterprise storage. Sure, it’s not optimized for RAID environments like Western Digital’s enterprise-class products, but the power savings will add up in multi-drive environments.

Lower power consumption was Western Digital’s primary goal with the GreenPower, and they’ve nailed it. The Caviar GP is the most power-efficient drive we’ve ever tested, and that’s saying a lot considering its terabyte capacity. No other high-capacity drive even comes close, and Hitachi’s terabyte Deskstar sucks twice the power of the GP under load.

We expected the GreenPower to be energy-efficient. What we didn’t expect was the drive’s incredibly low noise levels. The GreenPower makes less noise than any other 3.5″ drive we’ve tested, particularly at idle, where it’s barely audible. That makes this drive perfect for home theater PCs, where its terabyte capacity is ripe for HD recording, and also for silent desktops where noise levels take precedence over performance.

The icing on the cake for the Caviar GP is the fact that the drive is actually quite affordable. With street prices as low as $288 online, the GreenPower is 10% cheaper than its nearest terabyte rival. That sounds just about right given the drive’s performance, making it easy to recommend the Caviar GP to anyone looking to lower his PC’s noise levels or power consumption.