Toshiba today announced that it has launched a new lineup of high performance 2.5-inch HDDs destined for notebooks, including the flagship 400GB MK4058GSX. While this is not as capacious as the 500GB drives announced earlier in the year by Hitachi, Samsung and Fujitsu, Toshiba says this is the highest areal density ever in a disk drive at 477Mbit/mm (308Gbpsi), with the 400GB spread over only two platters.

The new drive spins at 5,400rpm and offers reduced energy consumption – it is approximately 20 percent more efficient than Toshiba’s current top-of-the-line 320GB MK3252GSX. It also features a ‘silent seek function’, which uses acoustic dampening techniques to reduce noise during disc activity. Along with this drive, Toshiba also announced five new 7,200rpm drives available in capacities of 80GB, 120GB, 160GB, 250GB, and 320GB.

Mass production will start in August for the 7,200rpm units and in September for the 400GB drive – no pricing details were given at this time.