Hitachi's deskstar 7K400 is the new king of big: The 7200-rpm Serial ATA hard drive comes with an 8MB buffer and a staggering 400GB of storage. The reasonably priced drive, available in the USA at $400 (£217), also features improved digital-media handling capabilities. In tests it performed exceptionally well on standard desktop applications, too.

To reach 400GB in the new model, Hitachi essentially slipped two more 80GB platters into its 250GB Deskstar 7K250. Adding the extra platters didn't affect performance: The 7K400 completed tests at PC World magazine (PC Advisor’s US sister magazine) in 34 minutes, 1 second, 21 seconds slower than the 7K250, a statistical tie. In both Windows and applications-based tests, it outperformed the average score of all seven 200GB or larger hard drives seen, often by 9 to 16 percent.

The drive is not only speedy; Hitachi says it also excels at streaming video, a key function of set-top, TiVo-like boxes and of PCs used as digital video recorders, thanks to its new streaming command set. When used with compatible software, the industry-standard technology alters the drive's error-correcting functions during video streaming to permit minor errors rather than stopping the stream for correction. Although such errors are unacceptable in PC data, this results in smoother video, with rare, blink-and-you-miss-it imperfections. Hitachi says users should be able to turn this feature on and off.

Better streaming abilities aside, this is one fast drive. And at $400, it's a fairly economical way to prepare a new or existing media-savvy PC for high-definition content, where each hour of video can require 8GB or more.

The deskstar 7K400 will be available in the UK in around a month, pricing to be confirmed.