WD launches the 640GB HDD

Western Digital has bumped up the capacity of its two-platter SATA drives to 640GB, an increase of almost a third, and is planning more drives based on its latest 160/320GB disk technology.

The new 640GB Caviar SE16 drive, which lists for £85, follows on from a single-platter 320GB model. WD said that it offers a 3Gbit/s data transfer rate, spins at 7200 RPM, and has 16MB of cache memory.

Although it might look like a 320 with an extra platter - and indeed, the platters and heads are the same - the 640GB drive is actually a separate product with some new parts, such as the motor, said Ted Deffenbaugh, WD's senior director of product marketing.

He explained that single-platter drives are aimed at the entry level market, where "acoustics are critical", so they are tweaked to run almost silently at the expense of a little performance. Two and three-platter drives are "more performance-optimised, even though that means a bit more seek noise."

Deffenbaugh acknowledged that 640GB is a rather unusual capacity point, and said he doesn't expect to sell too many to commercial desktop buyers.