Filed under: StorageToshiba just bested its own 320GB hard drive with a 400GB offering in the same 9.5-mm height form factor favored by most thin laptops. That's as good as it gets unless you can track down Sammy's elusive 500GB Spinpoint M6. The MK4058GSX spins just 2 platters which means the disk sports an impressive 477Mbit/mm2 (308Gbpsi) areal density while consuming 20% less power (0.0015W/GB energy consumption efficiency) and 2dB less no
