We've been waiting for that refresh for a couple of years now, and Western Digital finally tipped its hand in January when it announced the Raptor WD1500. The drive retains the Raptor's 10K-RPM spindle speed and Serial ATA interface, but adds a beefier cache, larger total capacity, and support for Native Command Queuing. Just days later, Western Digital pulled back the curtains on the Raptor X, a version of the WD1500 with a window on the drive's internals. That's right: a hard drive window.
The Raptor X shares the WD1500's updated internals, and apart from the better view, it's identical to its enterprise-class counterpart. But how does it perform? We've cornered one in our labs and subjected it to an exhaustive set of synthetic and application tests to find out.
From an aesthetic perspective, hard drives tend to be rather dull. Not the Raptor X, though. It's dressed in black and features a unique window that offers a glimpse at the mirror-like finish of the drive's platters and one of its heads. The view is even more impressive with the drive powered on, as the platter spins and the drive head darts from track to track. Check out a video of the drive head in action here. There isn't any real utility to the drive window, though. One could perhaps use it to diagnose a head crash or other mechanical failures, but it's really just for show—showing off, that is. When you're running what may be the fastest Serial ATA hard drive on the market, you might as well show off its internals. Think of it like an engine window on a Ferrari F430.
Of course, Ferraris don't come cheap, and neither does the Raptor X. The drive carries a $50 price premium over the Raptor WD1500, which lacks the window but is otherwise identical to the Raptor X.
Apart from the WD1500, the Raptor X's closest competitor is its predecessor, the Raptor WD740GB. Here's how the new drive's specs compare.
|Raptor X||Raptor WD740GD|
|Maximum external transfer rate||150MB/s|
|Maximum internal transfer rate||84MB/s||72MB/s|
|Read seek time||4.6ms||4.5ms|
|Write seek time||5.2ms||5.9ms|
|Average rotational latency||2.99ms|
|Idle power consumption||9.19W||8.40W|
|Read/write power consumption||10.02W||7.90W|
|Warranty length||Five years|
Perhaps the biggest difference between the Raptor X and the WD740GD is the former's higher density platters. New 75GB platters allow Western Digital to squeeze 150GB out of a two-platter design, giving the Raptor X twice the capacity of the previous generation. Platters with a higher areal density do more than just increase the drive's storage capacity, though. Greater areal densities allow the drive head to access the same amount of data over a shorter physical distance, resulting in higher sustained transfer rates.
In addition to doubling the WD740GD's total capacity, the new Raptor also doubles its predecessor's cache size from 8MB to 16MB. Support for Native Command Queuing (NCQ) has been added, as well. The WD740GD actually supports a form of command queuing known as Tagged Command Queuing (TCQ), but storage controllers with TCQ support have been few and far between. Support for NCQ is far more common—nearly universal among high-end core logic chipsets.
Despite several new features, the Raptor X has the same 10K-RPM spindle speed as previous Raptors. Write seek times are more than half a millisecond faster with the new drive, at least according to Western Digital's spec sheet. That might not seem like a lot of time, but with processors pushing billions of instructions per second, it's a virtual eternity inside a modern PC.
Speaking of eternities, the original 150MB/s Serial ATA interface has been around for a while now. Newer SATA hard drives and storage controllers have moved on to support 300MB/s transfer rates, but the Raptor X tops out at only 150MB/s. Western Digital says it hasn't been able to get 300MB/s transfer rates working perfectly with a wide enough variety of disk controllers, so it has taken a conservative approach with the Raptor X. Since not even 15K-RPM SCSI drives can sustain fast enough transfer rates to saturate a 150MB/s connection, the Raptor X's lack of support for 300MB/s transfer rates shouldn't be a huge drawback.