Add another color to Western Digital's rainbow of mechanical hard drives. To complement its 3.5" Black, Blue, and Green families, WD has rolled out the Red. This new SATA model is targeted at network-attached storage for the home and small businesses. The Red isn't quite an enterprise-grade product, but it has been optimized to play nicely with the RAID controllers typically found in NAS devices. RAID controllers offer their own error-correction mechanisms, so they don't expect connected drives to chase down errors. If a drive spends too long attempting solo error recovery, it can be deemed unresponsive and dropped from the array prematurely. The Red's error recovery is time-limited to prevent that from happening.
RAID arrays often stack multiple drives in relatively small enclosures, and the Red has been designed to withstand the additional vibration and higher temperatures typical of those environments. It's meant to run 24x7, too, and has a Mean Time Between Failure rating 35% higher than WD's standard desktop drives. The Red also benefits from a longer warranty: three years, versus two for the WD Blue and Green. The WD Black remains one of very few desktop drives with five-year warranty coverage.
Unlike the 7,200-RPM Black, the Red has an "IntelliPower" spindle speed, which is WD's way of saying "about 5,400 RPM." That's plenty quick for home NAS implementations, and the lower rotational speed should help to reduce operating temperatures and noise levels. WD claims the Red runs several degrees cooler than the competition, although it's unclear whether the competing drive has a similar spindle speed.
Western Digital touts the Red's compatibility with a slew of NAS devices from all the big names. The drive is intended to be an upgrade option for those devices, and it should work just fine in standard PCs. You can buy one today, too. Newegg has the terabyte version for $110, the 2TB model for $130, and the 3TB variant for $180. Those prices are about $10 higher than what Newegg charges for Western Digital's Green drives. I'd pay the premium for network-attached storage, not only for the RAID optimizations, but also for the longer warranty. Of course, the Green drives used to have three-year warranties of their own.