Western Digital’s Caviar Green hard drive

Western Digital has long been a performance leader in the hard drive world. That made it especially odd when the company debuted its first terabyte in the “GreenPower” Caviar GP. Despite what enthusiasts might have hoped, GreenPower didn’t mean “Hulk smash.” Instead, it referred to the drive’s eco-friendly motor, whose slower spindle speed dramatically reduced power consumption. WD had driven to the terabyte party not in a performance-oriented sports car, but behind the wheel of a tree-hugging econobox.

To be fair, the Caviar GP’s performance was surprisingly good for a drive whose platters spun at close to 5,400RPM. In some tests, it was even faster than terabyte drives spinning at a full 7,200RPM. The GP also lived up to its energy-efficient billing, sucking half the power of some of its terabyte rivals, all while barely making a whisper.

Since its release, a reshuffling of Western Digital’s hard drive branding scheme has transformed the Caviar GP into the Caviar Green. Now it’s time for the drive itself to change. The original Caviar GP reached the terabyte mark with four 250GB platters, but the latest model we’ll be looking at today has been upgraded to 333GB platters, of which it needs only three.

The higher areal density of the Caviar Green’s new platters promise improved performance, and since the drive is spinning only three of them, power consumption should drop as well. On all fronts, then, this latest Caviar Green looks better than the original. Let’s see if it is.

A denser shade of green
The idea behind the Caviar Green is a simple one. For some applications, be they home theater PCs, secondary desktop storage, or a home file server stuffed into a closet, you don’t need the fastest hard drive on the block—just one that’s fast enough. Those markets are likely to prefer drives with lower noise levels and power consumption, which the Caviar Green is more than eager to provide, ideally while maintaining an acceptable level of performance.

It might be counter-intuitive for an enthusiast to give up any performance, but the trade-off makes sense here. At least in consumer markets, most folks buy hard drives looking to expand storage capacity for their multimedia libraries. You don’t need a fast hard drive to store or smoothly stream even the highest definition video content, and your multi-gig MP3 collection certainly doesn’t need to be on a 10K-RPM VelociRaptor.

When it first launched the GreenPower Caviar, WD refused to disclose the drive’s actual spindle speed, saying only that it was somewhere between 5,400 and 7,200RPM. The company later admitted that the drive ran at closer to the former than the latter, but we haven’t been able to coax out an exact spindle speed.

Numerous sites have speculated that the Caviar Green essentially runs at 5,400RPM, and now even Western Digital has changed its tune. Sort of. The drive’s latest spec sheet lists the Green’s rotational speed as “IntelliPower,” which WD defines as “A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance.” So much for clarification.

Western Digital obviously doesn’t want customers making assumptions about the Caviar Green’s performance based on rotational speed alone, but the decision to obfuscate it behind blatant marketingspeak is entirely unnecessary and evasive. After all, the market isn’t short on examples of drives with slower spindle speeds outperforming faster ones. One need look no further than our most recent mobile storage round-up to see Western Digital’s own 5,400-RPM Scorpio Blue beating Seagate’s 7,200-RPM Momentus in some tests. Consumers deserve a little more credit. Those nerdy enough to dig through data sheets or online reviews to find a drive’s spindle speed are going to know that it’s not the only factor that dictates performance.

Enough with the soapbox, though. We have a drive to test. The latest addition to the Caviar Green lineup can be identified by its WD10EADS model number. You’ll want to write that down, because the old drive’s model number is WD10EACS. The drives themselves are quite similar, with the biggest difference coming on the platter front. Western Digital has replaced the original’s quartet of 250GB platters with a trio of platters that weigh in at 333GB each. This 33% increase in areal density enables the Green to offer a terabyte with fewer platters, allowing the motor to spin less weight, which further reduces the drive’s already low power consumption. The higher areal density of these new platters should also improve the Green’s sustained transfer rates by spinning more bits past the drive head in a given span of time.

Western Digital’s second GreenPower upgrade is applied to the drive’s cache, which has been bumped from 16MB in the original to 32MB in this latest model. For quite some time, WD insisted that its own internal performance testing showed little benefit to cache sizes larger than 16MB. The company’s recent jump to 32MB may be more to keep up with the Joneses than anything else.

Apart from new platters and more cache, the latest Caviar Green shares the same mechanical underpinnings and features of its predecessor, including the IntelliSeek just-in-time drive head delivery mechanism. Rather than racing the drive head across the disk as fast as possible, IntelliSeek uses rotational latency to its advantage, only moving the drive head as fast as necessary to get it into position for the next data point. Western Digital claims IntelliSeek can lower not only drive power consumption, but also seek noise levels and drive vibration.

Like most hard drives, the Caviar Green is covered by a three-year warranty. That’s still two years short of Seagate’s across-the-board five-year warranty, although it’s worth noting that Western Digital covers its high-end Caviar Black drives with a five-year term.

Test notes
We’ll be comparing the performance of the Caviar Green with that of a slew of competitors, including some of the latest and greatest Serial ATA drives from Hitachi, Samsung, Seagate, and Western Digital. These drives differ when it comes to external transfer rates, spindle speeds, cache sizes, platter densities, and capacity, all of which can have an impact on performance. Keep in mind the following differences as we move through our benchmarks:

To differentiate between Western Digital’s GreenPower Caviars, we’ll be referring to the old model by its maiden name: Caviar GP. Since the new model’s WD10EADS distinction is a little awkward, we’ll be calling it the Caviar Green. You’ll want to pay particular attention to how the Caviar Green stacks up against not only the GP, but also the Caviar Black, which spins WD’s 333GB platters at 7,200RPM.

Performance data from such a daunting collection of drives can make our bar graphs a little hard to read, so we’ve colored the bars by manufacturer, with the Caviar Green appearing in brighter blue than the rest of Western Digital’s drives.

Our testing methods
All tests were run three times, and their results were averaged, using the following test system.

Thanks to NCIX for getting us the Deskstar 7K1000 and SpinPoint F1.

Our test system was powered by an OCZ PowerStream power supply unit.

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
• 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
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 Caviar Green isn’t the fastest drive in WorldBench, and it’s not any quicker than its predecessor. However, this suite of application tests nicely illustrates the fact that you don’t need a fast hard drive for most common desktop tasks. Only four points separates the fastest from the slowest here.

Multimedia editing and encoding

MusicMatch Jukebox

Windows Media Encoder

Adobe Premiere

VideoWave Movie Creator

Of WorldBench’s multimedia editing and encoding tests, the field only really separates in Premiere. The Caviar Green is the slowest of the bunch in that test, trailing even its 250GB-per-platter forebear.

Image processing

Adobe Photoshop

ACDSee PowerPack

ACDSee gives the Green a chance to strut its stuff a little. WD’s freshest eco-Caviar is even quicker than the Caviar Black here, and certainly faster than the old Caviar GP.

Multitasking and office applications

Microsoft Office

Mozilla

Mozilla and Windows Media Encoder

WorldBench’s multitasking and office tests are largely unaffected by our choice of hard drive.

Other applications

WinZip

Nero

However, WorldBench’s Nero and WinZip components definitely stress the storage subsystem. In the latter, the Caviar Green delivers exactly the same performance as the GP. Things don’t look as rosy in Nero, where the Green falls to the back of the pack, more than 20 seconds behind its predecessor.

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

Despite its platter density advantage, the Caviar Green boots slower than the GP by nearly five seconds. That makes it one of the slowest drives of the bunch in this test.

Fortunately, the Green redeems itself somewhat when we turn to level load tests. It’s a middle-of-the-pack performer here, and more importantly, faster than the Caviar GP.

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 separated our FC-Test results into individual graphs for each test pattern. We’ll tackle file creation performance first.

FC-Test gives the Caviar Green an opportunity to stretch its new platters, and the drive easily outpaces the GP in this first wave of write speed tests. Note that the Caviar Green is also much quicker than Seagate’s 7,200-RPM Barracudas, including the new 1.5TB model, which packs a whopping 375GB per platter.

The Green manages to stay out ahead of some of the Barracudas through FC-Test’s read speed tests. Again, the latest GreenPower is quite a bit quicker than the original Caviar GP.

FC-Test – continued

Next, File Copy Test combines read and write tasks in some, er, copy tests.

The Caviar Green stays in the middle of the pack. The old Caviar GP just can’t keep up with the new drive’s denser platters and larger cache. Neither can a number of 7,200-RPM drives, for that matter.

The results of FC-Test’s partition copy, er, tests, shake out much like those of the earlier copy tests.

iPEAK multitasking
We’ve developed a series of disk-intensive multitasking tests to highlight the impact of seek times and 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.

Disk-intensive multitasking proves a little challenging for the Caviar Green. The latest addition to the GreenPower family can’t keep up with the Caviar GP with workloads that pair a VirtualDub import operation with compressed file creation and extraction, but it is quicker with the other three workloads.

Our second batch of iPEAK workloads plays out much like the first. The Caviar Green struggles when a VirtualDub import is paired with other tasks, but fares better otherwise.

If we average the response times for each drive across all our iPEAK workloads, the Caviar Green ends up in ninth place, just ahead of the Caviar GP.

IOMeter
IOMeter presents a good test case for both seek times and command queuing.

Western Digital has a history of releasing enterprise-optimized derivatives of its GreenPower drives, so it’s a good thing the Caviar Green handles multi-user IOMeter workloads with aplomb. The Green may not come close to the transaction rates delivered by the Caviar Black or VelociRaptor, but it offers better performance than 7,200-RPM drives from Hitachi, Samsung, and Seagate.

IOMeter CPU utilization is low across the board.

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

Despite the high areal density of its 333GB platters, the Caviar Green’s slower spindle speed holds the drive back in HD Tach’s sustained throughput drag race tests. At least the Green is a lot quicker here than the original Caviar GP.

In an attempt to sleuth the Green’s actual spindle speed, I did a little math on these results. The Caviar Green and Caviar Black both feature three of Western Digital’s 333GB platters backed by 32MB of cache, and we know that the Black’s platters spin at a full 7,200RPM. Assuming that all other elements of the Caviar Green and Black are equal (which they’re not), a little arithmetic suggests that the Green’s platters could be spinning at up to 6,300RPM.

So maybe the new Caviar Green spins much faster than 5,400RPM. Or maybe it doesn’t, and HD Tach sustained data rates simply don’t lend themselves to simplistic spindle speed extrapolation. We wouldn’t have to resort to such convoluted analysis if Western Digital would reveal the Green’s spindle speed.

Spindle speeds have little effect on burst performance. The Green’s 32MB of cache memory is plenty quick in this test.

This latest version of the Caviar Green improves upon the GP’s random access time by a full millisecond. That puts the drive on-par with Samsung’s 7,200-RPM SpinPoint F1.

The Caviar Green’s HD Tach CPU utilization is well within the app’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.

The Green is within a fraction of a decibel of being the quietest drive we’ve ever tested.

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.

Dropping the Caviar Green’s platter count nicely improves its energy efficiency. The drive’s power consumption is about a watt lower than the Caviar GP at both idle and under load, making it the most power-efficient terabyte hard drive we’ve ever tested.

Conclusions
Adding 333GB platters and another 16MB of cache to the Caviar Green improves the drive on two fronts. As we’ve seen, the latest Green is generally faster than its 250GB/platter predecessor, no doubt thanks to its higher areal density. This attribute also allows Western Digital to bring the Green up to a terabyte using one less platter, which translates into about a watt of power savings overall. One watt isn’t much in the grand scheme of things, but for a drive that specifically targets power efficiency, it’s a notable improvement.

So the new Caviar Green offers better performance and consumes less power than Western Digital’s seminal GreenPower drive. And it’s just as quiet, practically speaking, making it all the more attractive than the original. There isn’t even much of a price premium associated with the new model. Although it just appeared online and is thus far only available from a handful of retailers, the new Caviar Green 1TB (be sure to look for model number WD10EADS) runs about $140—just $20 more than the original Caviar GP. I expect the price gap between the drives to shrink as the new model becomes more widely available.

Obviously, the Caviar Green is a poor choice if you’re looking for a lightning-quick storage solution. It may be fast enough for basic desktop tasks, but it’s much slower than the fastest terabyte drives on the market. The Green is really designed for applications that favor low power consumption and silent operation over raw performance. In its domain, it excels. If you’re building a power-efficient home theater PC or closet file server, or even if you’re looking to add secondary storage to an existing desktop, this latest Caviar Green should be at the top of your list.