Instead of focusing on the high end of mobile storage, Seagate today unveiled the Momenuts 5400.4 250GB. The Serial ATA II drive is built to make relatively large hard disks available outside of pro notebooks and as a low-cost upgrade for systems with easily swappable drives. Despite holding 125GB of data across a relatively small two platters, the drive is said to be more power-efficient and tolerant of shocks (up to 325 Gs when active) than earlier generations. An 8MB cache is standard.

The new 2.5-inch Momentus is the largest-capacity model in the 5400.4 line but should retail as an upgrade kit for $165, about $50 less than most other 250GB disks; notebook manufacturers are also likely to use the drive. Seagate is shipping the drive today and also tells Electronista that a 7200RPM drive will be available soon to provide performance closer to that of a 3.5-inch desktop disk.