Hitachi HGST 4TB 7200 RPM 64MB Cache SATA 6G 3.5" Hard Drive for Audio, Video, Gaming and External Storage Faster data processing - 64MB cache buffer SATA 6Gb/s interface. Advanced Format increases the sector size on HDDs from 512 bytes to 4096 (4K) bytes, thereby increasing capacities and improving error correcting capabilities. Thermal Fly-height Control (TFC) - better soft error rate for improved reliability and performance Advanced Power Management reduces power during idle periods Qualified for 24/7 operaration Eco-friendly, halogen-free design