It's almost amazing how this isn't more common but, in order to use its new 320 GB platters to the fullest, Western Digital has now released a 640 GB hard drive. The new 3.5-inch hard drive utilizes two 320 GB platters that feature PMR (perpendicular magnetic recording) technology and comes with Native Command Queuing (NCQ), a SATA 3.0 Gbps interface and works at 7,200 rpm.

"Two-platter hard drives have always been the perfect balance of value, capacity and performance for many of our customers," said Don Bennett, general manager and vice president of WD's desktop business unit. "Today's common two-platter drives are limited to 500 GB, but we are expanding capacity by 28 percent on the same design with WD's leading technology heads and disks."

The Caviar SE16 640Gb drive boasts a 16MB buffer and can already be found in WD's online store with a price tag of $139.99.