The big three drive manufacturers--Hitachi, Seagate, and Western Digital--each sent us a 3TB hard drive for testing. All three drives were very good performers when writing and reading large files, as well as when reading small files and folders. Two of them, the Hitachi Deskstar 7K3000 and Seagate Barracuda XT, did well in writing large amounts of small files, too, while the Western Digital Caviar Green (the drive that had the aforementioned alignment issue) struggled slightly in this scenario. Overall, the Deskstar 7K3000 was the best performer, albeit by only about 10% over the Seagate Barracuda XT. The WD Caviar Green lagged a little behind, but keep in mind that the Green is oriented toward conserving power. It varies its rotational speed between writes, which hurts it when copying lots of smaller files--one part of our testing. (Click the chart below to view it at full size.)
Another differentiator between the drives turned out to be the software. Hitachi includes a driver/partitioning utility (from Paragon Software) that allows you to utilize all 3TB in a single partition. By contrast, as of this writing, the Acronis software favored by Seagate and WD allows you to use the entire drive capacity, but only in separate 2.2TB and 800GB partitions. To create a single volume, you need to follow the previously mentioned tip about combining partitions using Windows dynamic disks.
The Hitachi Deskstar 7K3000 was not only the best performer in PCWorld Labs testing, but also the best bargain. It sells for about $120, compared with $150 for the Western Digital Caviar Green and nearly $200 for the Seagate Barracuda XT. That makes the 7K3000 the only drive of the three that competes on a cost-per-gigabyte basis with 2TB hard drives. One fortunate byproduct of the introduction of 3TB drives is a commensurate drop in the price of 2TB drives: 2TB units are now selling for as low as $75.
With such prices, most users seeking to upgrade--especially those with legacy or 32-bit Windows operating systems--will probably be better off purchasing two 2TB drives. Although 3TB drives are great, the current hassles and the relatively high price per gigabyte limit their usefulness on systems lacking the appropriate technology.