Ultrastar DC HC320 is based on a proven 5-disk air platform design that uses conventional magnetic recording (CMR) technology in a 3.5-inch large form factor. Compared to the prior generation, Ultrastar 7K6000, the DC HC320 delivers 33% more capacity, up to 12% performance boost and uses slightly larger-diameter media. It features a second-generation, dual-stage micro actuator to enhance head positioning accuracy for better drive performance. Write performance gains are also supported by Western Digital's media cache architecture, a disk-based caching technology that provides a large cache area on the disk, which also improves reliability and data integrity during unexpected power loss. Finally, the addition of flash-based non-volatile cache (NVC) helps improve write performance. The Ultrastar DC HC320 also includes a Rebuild Assist feature, which helps dramatically reduce RAID rebuild times and maintain system performance.