WD Ultrastar DC HC520 12TB SATA3 EnterPirse Internal Hard Drive ( HDD )

The Western Digital Ultrastar DC HC520 is a 12 TB enterprise-class internal hard drive engineered for demanding data-centre workloads. Built on fourth-generation HelioSeal technology, the drive's hermetically sealed helium-filled enclosure houses an eight-disk stack — a design that increases areal capacity by 20% compared to the seven-disk Ultrastar DC HC510 predecessor — while simultaneously lowering the internal air-resistance drag that limits conventional drives. Designed to sustain continuous workloads of up to 550 TB per year, the HC520 uses traditional perpendicular magnetic recording (PMR), making it a drop-in replacement for existing enterprise-capacity applications without requiring firmware or controller changes. A second-generation dual-stage micro-actuator refines head positioning, which improves data integrity and sustains performance in multi-drive environments where operational vibration is a concern. The drive's low-power helium platform delivers a meaningful reduction in watts-per-terabyte versus comparable air-filled drives, helping data-centre architects meet energy-efficiency and eco-environmental targets. The drive supports a 6 Gb/s SATA interface for straightforward integration into current-generation storage platforms. With a targeted mean time between failures (MTBF) of 2.5 million hours, the Ultrastar DC HC520 carries one of the higher reliability ratings available in the HDD segment. It is also well suited to object-storage deployments leveraging erasure coding, where its combination of high capacity and strong reliability provides an effective fit alongside modern data-durability architectures. Security-conscious environments are supported through optional TCG encryption on select SAS variants. All Ultrastar DC HC520 units are backed by a 5-year limited warranty and Western Digital's enterprise technical-support programme. Verifiable Specifications: - Capacity: 12 TB - Interface: SATA 6 Gb/s - Form Factor: 3.5 inch - Spindle Speed: 7,200 RPM - Cache (Buffer): 256 MB - MTBF: 2.5 million hours (targeted) - Workload Rating: Up to 550 TB/year - Recording Technology: PMR (Perpendicular Magnetic Recording) - Internal Atmosphere: Helium (HelioSeal, 4th generation) - Warranty: 5 years limited - Weight: approximately 1 kg