Western Digital's Caviar RE2 hard drive

Enthusiasts covet the Raptor for its blistering 10,000-RPM spindle speed and five-year warranty, but the drive's storage capacity stalled at 74GB over a year and a half ago. 74GB is peanuts by today's standards, and the Raptor's relatively high price tag makes for a cost per gigabyte that's grim at best. Fortunately, Western Digital recently launched an enterprise-class Caviar RE2 hard drive that offers more than five times the capacity of the 74GB Raptor. Weighing in at 400GB, the RE2 spins at 7,200RPM, boasts 16MB of cache, supports Native Command Queuing, and is covered by Western Digital's five-year enterprise warranty. Best of all, the drive's cost per gigabyte is actually lower than 400GB desktop drives from other manufacturers.

Technically, the Caviar RE2 is targeted at servers and network attached storage, but that hasn't stopped us from running the drive through a punishing gauntlet of performance tests that cover server, workstation, and desktop loads. Read on to see how the Caviar RE2 stacks up against Western Digital's best, and the fastest Serial ATA drives from Hitachi, Maxtor, and Seagate.

Drive specs
The newest Raptor is over a year and a half old, so it's better to compare the Caviar RE2's specs with Western Digital's most recent desktop offering, the Caviar SE16. Both drives spin at 7,200RPM and have 16MB of cache, although the similarities really end there.

One of the biggest differences between the Caviar SE16 and RE2 is support for 300MB/s Serial ATA transfer rates. We've found that 300MB/s SATA transfer rates have little impact on performance, so it's not a huge loss. Still, it's odd to see a new drive released without support for the faster interface speed, especially since Western Digital already supports it on the Caviar SE16.

What the Caviar RE2 lacks in peak host transfer rates it makes up for with support for Native Command Queuing (NCQ). Western Digital's Raptor WD740GD has supported Tagged Command Queuing (TCQ) from the beginning, but storage controllers with TCQ support are rarer than those that work with NCQ. With Native Command Queuing now under the umbrella Serial ATA 2.5 spec, TCQ's days may be numbered, anyway.

We should note that when Western Digital launched the Caviar SE16, which lacks NCQ support, the company claimed that command queuing could actually hurt performance with the kinds of streaming transfers that are typical in desktop systems. However, the enterprise environments that the Caviar RE2 is designed to tackle are generally defined by multi-user loads and more random I/O profiles that stand to benefit from NCQ's ability to intelligently re-order I/O requests. In any case, it will certainly be interesting to see how the Caviar SE16 and RE2 stack up in our streaming transfer tests.

Command queuing isn't the Caviar RE2's only potential performance ace; the drive also sports a higher areal density than Western Digital's top desktop drive. Denser platters allow a drive head to access the same amount of data over a shorter physical distance, reducing the performance impact of mechanical latency. Denser platters can also improve reliability by allowing drives to be built with fewer physical disks, but the Caviar RE2 stacks four 100GB platters, so it's still pretty packed.

The extra weight of four platters may explain why the Caviar RE2's power consumption is higher than that of the SE16. According to Western Digital's specs, the RE2 is also a little louder. Higher noise levels are to be expected from enterprise products. After all, they're designed for data centers, not the living room.

While enterprise customers may be less concerned with noise levels, good warranty coverage is a must. Five-year hard drive warranties are pretty standard for enterprise-class hard drives, and the Caviar RE2 is no exception. The drive's five-year pact is considerably better than the three-year warranty that covers most desktop Serial ATA drives, although it's worth noting that Seagate recently bumped warranty coverage for all its internal hard drives to five years.