A 400GB 2.5" notebook hard drive might not sound all that impressive if you've kept up with storage news lately—after all, Samsung announced a 500GB model that doesn't go over the 9.5-mm thickness limit back in March. However, that drive uses three platters, whereas Toshiba's 400GB MK4058GSX uses only two platters with a record 477Mbit/mm areal density.
Toshiba says it used an "improved read-write head and enhanced magnetic layer" to achieve such a high areal density. On top of that, the company made advances that allegedly result in 20%-higher energy efficiency (defined in terms of watts per GB) and 2dB-lower noise levels compared to Toshiba's former flagship, the 320GB MK3252GSX. Toshiba rates the MK4058GSX for a seek noise level of 25dB.
The MK4058GSX will hit mass production in September. A month before, Toshiba plans to start mass-producing a new line of 2.5" 7,200-RPM drives that includes 80GB, 120GB, 160GB, 250GB, and 320GB variants. These faster drives will pack 16MB of cache, and the 320GB MK3254GSY will also be more energy-efficient than its predecessor, with 37%-lower W/GB than the 200GB MK2049GSY. These latest drives feature optional free-fall sensors to protect them from crashes, too.