Seagate ST3400633AS-RK 400GB Barracuda 7200 SATA Internal Hard Drive 16 MB cache provides the highest performance with increased data bursting through the interface Super-quiet drive is almost inaudible 7200 RPM spindle Best-in-class operating and non-operating shock for excellent reliability SATA 3Gb/s drive with NCQ supports Intel Hyper-Threading for increased performance