For quite a long time, there were three performance tiers for desktop hard drives. At the bottom, 5,400-RPM models served as the sensible baseline for those simply looking for storage. 7,200-RPM drives lived one notch higher on the ladder, offering much better performance while still being practical enough for mainstream desktops. And then there was the final tier: even faster 10,000-RPM monsters that migrated over from the world of enterprise-class workstations and servers.
Enthusiasts have always had a weakness for enterprise gear. Longer ago than I'd care to admit remembering, we couldn't get our hands on hard drives that spun their platters faster than 7,200-RPM without dipping into expensive SCSI territory. Then along came Western Digital's Raptor. Ostensibly designed for enterprise, this 3.5", 10k-RPM hard drive conveniently came with a Serial ATA interface that plugged into just about any new desktop motherboard on the market. The first incarnation may only have offered 37GB of storage capacity at a time when other desktop models were pushing hundreds of gigabytes, but the Raptor line eventually spawned far more practical 74 and 150GB variants. Western Digital even gave enthusiasts a nod with a special windowed edition dubbed the Raptor X.
For its last Raptor reboot, WD followed an enterprise storage trend that's seen 3.5" drives give way to 2.5" models that can be more densely packed into rack-mount servers. The resulting VelociRaptor had the same footprint as traditional mobile drives, albeit with a 15-mm drive heighttoo tall to slip into notebooks designed for drives only 9.5 mm thick. Despite its Yoda-like proportions, the VelociRaptor doubled its predecessor's capacity with 300GB of storage. WD even wrapped the drive in a 3.5" sled that conveniently slid into standard enclosure bays.
New Raptor models have come out roughly every two years since the first one was launched. Impressively, each drive has set a new performance standard upon its release. Nearly two years have passed since the VelociRaptor made its official debut, and wouldn't you know it, Western Digital has just hatched a new one. The latest VelociRaptor VR200M retains the same 2.5" form factor as its forebear, but it's been working out and has bulked up to an impressive 600GB.
Before you think that we're in for another raising of the performance bar, consider that a lot has happened in the storage world over the past two years. Just a couple of years ago, solid-state drives were rare, impractical, and stupendously expensive. Today, they're far more common, actually quite usable, and finally starting to flirt with being justifiably affordabledepending on your budget, anyway. The question we face is obvious: can the new VelociRaptor compete in this rapidly evolving storage market, or has it become, well, a dinosaur?
The VelociRaptor evolved
The latest addition to the VelociRaptor family is an evolutionary upgrade rather than a radical departure. WD hasn't changed the form factor at all, although it has updated the IcePack drive sled since the original VelociRaptor's launch. The first revision's SATA connectors weren't in the usual spot, creating problems for hot-swap bays. An auxiliary circuit board now situates the sled's Serial ATA ports in the correct location. (Current-generation VelociRaptors have been available with this design for a while.)
Of course, if you won't be installing the VelociRaptor in a 3.5" bay, you can order it without the IcePack. The sled might look like a giant heatsink, but it's not necessary to cool the drive. Remember that the VelociRaptor was designed to live in high-density servers.
Speaking of density, the VR200M's most impressive attribute may be its 600GB storage capacity. Western Digital pushed capacity on two fronts, upgrading the old two-platter design to three platters and increasing the capacity of each from 150 to 200GB. The result is an impressive feat of miniaturizationthree 200GB platters spinning at 10,000 RPM within the confines of an enclosure that's only a few millimeters thicker than most smartphones.
Western Digital hasn't disclosed the actual areal densities of the platters inside either the old or the new VelociRaptors. However, a little deduction and simple math can help us estimate how many more bits per square inch the VR200M squeezes onto its platter than the old VR150M. According to official spec sheets, the VR200M's maximum sustained data rate is 145MB/s, which is 13% faster than that of the VR150M. Since the drives share a common spindle speed and platter dimensions, we can infer that the VR200M's linear density is likewise 13% higher. If my math is right, that translates to a 28% increase in areal density, which is slightly less than the 33% jump one might have assumed looking at platter capacities alone.
|VelociRaptor VR150M||VelociRaptor VR200M|
|Maximum external transfer rate||300MB/s||600MB/s|
|Spindle speed||10,000 RPM|
|Available capacities||150, 300GB||450, 600GB|
|Maximum sustained data rate||128MB/s||145MB/s|
|Full-stroke seek time||8.5 ms|
|Average seek time||3.6 ms|
|Track-to-track seek time||0.75 ms||0.4 ms|
|Idle acoustics||27 dBA|
|Seek acoustics||34 dBA|
|Warranty length||5 years|
The VR200M's higher areal density pushes tracks closer together than on the VR150M, making the former quicker when seeking from track to track. However, WD quotes the same average and full-stroke seek times for both drives. The smaller bits on higher-density platters actually make maintaining fast random access times more difficult, so there's something to be said for the VR200M holding the line here.
Western Digital has added a 32MB cache to this new VelociRaptor, doubling the old model's 16MB cache. The 32MB cache may indeed be adequate from a performance perspective, but it still feels a little chintzy considering the fact that WD's top-of-the-line Caviar Black drives sport 64MB caches. Even low-power Caviar Greens are available with 64MB of cache, which makes putting 32MB on a marquee VelociRaptor seem a little short-sighted.
More puzzling than the VR200M's cache size is the drive's swanky new 6Gbps Serial ATA interface. There might be a small chance that this latest VelociRaptor can burst data from its cache quicker than the prior SATA standard's 300MB/s limit, but the drive's own spec sheet confirms that it can't sustain even half that speed. I don't imagine the faster interface is needed at all.
Curiously, the VR200M's dual-core drive controller is shared with Western Digital's RE4 2TB, which is a 7,200-RPM drive with a 3Gbps SATA interface. The RE4 is an enterprise-class model, which could explain the shared controller. After all, the VR200M does offer a number of enterprise-specific features. Support for Time-Limited Error Recovery (TLER) prevents RAID arrays from marking disks as bad prematurely, should they end up chasing down errors for too long. Also, the Rotary Acceleration Feed Forward (RAFF) capability allows the VR200M to maintain performance in tightly-packed arrays by compensating for environmental vibration.
Taking a page from its recent desktop drives, Western Digital has added NoTouch ramp loading technology to the new Raptor. This feature moves an idle drive head completely off the platter rather than letting it rest on the surface. WD claims NoTouch reduces wear on the drive. In fact, the VR200M is apparently capable of enduring 600,000 head unload and unload cycles12 times more than the VR150M. Both drives carry mean time between failure ratings of 1.4 million hours, though. Western Digital's five-year warranty coverage for enterprise-class hard drives persists, as well.
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