Origin Storage 320GB Precision M6400/6500 2.5in 5400Rpm Media bay (2nd) HD Kit, 320 GB, 5400 RPM, 2.5", Serial ATA Origin Storage 320GB Precision M6400/6500 2.5in 5400Rpm Media bay (2nd) HD Kit. HDD capacity: 320 GB, HDD speed: 5400 RPM, HDD size: 2.5", Interface: Serial ATA