3 TB: Hitachi Deskstar 7K3000 (HDS723030ALA640)
Hitachi’s second 3 TB drive spins at 7200 RPM and has 64 MB of cache memory. As a result, its specified throughput is much higher: 1656 Mb/s instead of 1366 Mb/s (that's 207 versus 170 MB/s). Real-world throughput reaches up to 152 MB/s according to h2benchw and 148 MB/s in our Iometer streaming reads test. These are commendable results that are only beaten by the new Deskstar 7K4000 and Seagate’s Barracuda 3 TB, which actually gets close to 200 MB/s.
The 7K3000 family is also available in 2 TB and 1.5 TB flavors, and they’re all specified for 24/7 operation. Power consumption is higher on this 7200 RPM drive than on Hitachi's 5K3000. That's simply the price you have to pay for higher throughput. We measure 4.9 W at idle for the 5400 RPM 3 TB drive and 7.1 W at idle on this 7200 RPM model. The 4 TB versions have very similar power requirements.
Since the performance difference between the 3 and 4 TB drives isn't too significant, we again have to recommend that anyone shopping for a high-capacity disk consider living with the 3 TB model if the last gigabyte isn't absolutely imperative. You simply spend a lot less money per gigabyte when you compromise down to the smaller drive.
You can find comprehensive hard drive performance comparison in our 2012 Desktop HDD Charts.