For comparison we had to rely on previously recorded results as we no longer have the drives in question. This is why we don't have complete results for all the other drives. Nonetheless, we've compared to the Seagate Barracuda 7200.11 1TB, the Hitachi 7K1000 1TB, and, to show what a performance drive can do, the Western Digital VelociRaptor 300GB.
Starting with the HDTune results, it's clear that despite the power saving enhancements, this drive still competes in terms of access time with both the Seagate and Hitachi 1TB drives and actually beats them on average transfer rate. We don't have write results for these drives but, in isolation, the Western Digital 2TB Caviar Green seems just as accomplished when writing data as it does when reading.
In PCMark the WD 2TB Caviar Green again beats the Hitachi 1TB drive and in fact, in all our remaining tests, this 2TB, apparently low-power drive, beats the conventional 1TB drives from Seagate and Hitachi.
Unfortunately, testing the power draw of a hard drive is incredibly difficult to do because, when idling, the spindle motors switch off and the drive does nothing and when being worked hard, the power reading will jump around all over the place. The only way to properly test for power usage is thus to take a total energy consumption (Power x Time) reading while doing a number of tasks and judge from that. Sadly we don't have the equipment to perform such a test so for the time being we'll have to take WD's word on the power saving figures.
Of course, the most important thing for most people when they consider whether it's worth investing in one of these drives is how much it costs. If it's significantly cheaper to buy two 1TB drives then it's a hard sell in most situations. Thankfully, then, Western Digital has kept the pricing sensible with this drive only just breaking the £200 mark, making it only about £30 more than buying two 1TB drives.
Western Digital is first to the 2TB party and it has made an impressive entrance. While it's no performance demon, the WD Caviar Green 2TB has all the power saving credentials that we now crave, is quiet, and is sensibly priced.