HGST Ultrastar 7K6000 4TB 7200 RPM SATA 128 MB Cache 3.5" Internal Bare or OEM Enterprise Hard Drive - HUS726040ALE610 / 0F23005 Excellent random write and sequential performance Capacity  Up to 4TB enterprise-class storage on HGST's proven 7th generation, 5-disk platform Performance  Up to 3X faster random writes and 25% faster sequential performance over 7K4000 12Gb/s SAS & 6Gb/s SATA  12Gb/s SAS for high performance data centers; compatible with 6Gb/s SAS Advanced format 4Kn and 512e models