MK6475GSX, A0/GT001M, HDD2L02 B UL01 T, Toshiba 640GB SATA 2.5 Hard Drive 640 GB Storage Capacity, SATA/300 interface 5400 RPM spindle speed, 8 MB buffer 12 ms average seek time, 2 ms track to track seek time 2.5-inch form factor, 9.5 mm drive height