Today Seagate takes the wraps off the latest addition to its family of 2.5" mobile hard drives: the Momentus 5400 640GB. As one might expect, the drive packs 640GB of storage capacity spread across two 320GB platters. Those platters have an areal density of 507 Gb/in², which is quite a jump from the 394 GB/in² that Seagate crams onto the 250GB discs that fuel its 500GB mobile drives.
The rest of this new Momentus fills out as one might expect; it has a 5,400-RPM spindle speed, an 8MB cache, and a 3Gbps SATA interface. Seagate says you can expect to see the drive available for sale this month. Western Digital's 2.5" Scorpio Blue 640GB currently sells for $120, and I'd expect this new Momentus to carry a similar price tag.
Incidentally, Seagate recently simplified the naming scheme for its mobile hard drives. Using the company's previous convention, the new Momentus should be known as the 5400.7: 5400 for the spindle speed and 7 for the generation. The decimal has been dropped moving forward, with Momentus drives identified simply by their spindle speed and capacity. Seagate also has a line of Momentus Thin drives targeted at netbooks and ultraportables. These single-platter drives measure 7 mm tall, which is 2.5 mm shorter than typical 2.5" hard drives. Only 160 and 250GB models are available at present, both of which spin at 5,400 RPM.