Western Digital Ultrastar DC HC550 18 TB

This is a 18000GB 3.5" HDD on the SATA interface. Sequential throughput reaches 550 MB/s reads and 520 MB/s writes, backed by 512MB of cache. At roughly $0.04 per gigabyte it sits in the premium tier. SATA throughput caps near 550 MB/s — fine for game libraries and backups, slower for heavy scratch work.

Expect to pay around $694.45, which lands it among premium options. Use the PlanMyPC system builder to verify it works alongside your other components and to watch live retailer pricing. Support and warranty service run through Western Digital, with terms that vary by region. Every published spec is tabulated below, and compatibility against your current part list is checked automatically.