3 TB: Western Digital Caviar Green (WD30EZRX)
The only 3 TB hard drive from Western Digital is a Caviar Green model, which aims at energy efficient systems. The drive is different from all the others in that it pairs a 5400 RPM spindle speed with 64 MB of cache and 3 TB of capacity. The company’s strategy includes the VelociRaptor drive, which recently hit 1 TB. That's WD’s performance family, which clearly outperforms any other mechanical hard drive aside from some of the enterprise-oriented models out there. So, a line of 7200 RPM 3.5” disks simply wouldn't make as much sense for Western Digital.
The Caviar Green drives come with a two-year warranty, while the Caviar Black and VelociRaptor families are backed by five-year coverage. This is similar to Seagate’s approach to the Barracuda and Barracuda XT. The Caviar Green is the slowest hard drive in this round-up in terms of throughput (122 MB/s max), but also in many of the I/O tests. Does that matter? If you're only leaning on the drive for archiving data, not really. But it would if you planned on running applications from it dependent on high throughput.
The Caviar Green WD30EZRX starts at around $170 (160 Euros in Europe). If you don't need 24/7 availability, you might want to consider Seagate's Barracuda as an alternative. It runs cooler and delivers more performance. It isn't designed to run all day and night, just like this Western Digital disk.