HGST Hitachi HMS5C4040BLE640 MegaScale DC 4000.B 4TB 3.5" 5700RPM 64MB Cache SATA III 6GB/s Internal HDD Hard Disk Drive 0F22146. HGST MegaScale 4000 leverages CoolSpin technology to provide the best power efficiency (watts/TB) available for datacenter capacity. HGST 4TB SATA III hard drive designed for enterprise level data backup. Home users can use it as an additional drive for back up. The MegaScaleDC 4000 is designed to meet the needs of the scale-out data center where low-power, high-capacity, cost-effective storage is essential. MegaScale DC addresses low application workloads that operate within 180TB per year. Typical low-workload applications include multi-drive replicated environments, disk-to-disk backup and restore snapshots, online archives, big data stores and long-term data retention that benefit from low-cost or energy usage.