Western Digital Caviar Black WD6401AALS 640GB 7200RPM 32MB 3.5" SATA internal hard drive

640 GB desktop hard drive

This 640 GB 3.5 inch SATA drive spins at 7200 RPM with a 32 MB cache. It suits builders adding bulk storage to a desktop tower or replacing an older mechanical disk. The SATA 3 Gb/s interface fits standard motherboard ports without adapters. Buyers needing solid-state speed or capacities above one terabyte should look elsewhere.

Sustained throughput on mechanical media

Sequential transfers hold steady at the rate allowed by the 7200 RPM platters and 32 MB buffer. Random access follows mechanical seek limits rather than burst caching. The drive maintains consistent output during long copies, backups or video capture sessions. Workloads demanding SSD-class latency or sustained writes above the native media rate will saturate the mechanism.

Thermals noise and power in normal use

The unit weighs 2.0 pounds and fits standard 3.5 inch bays with typical mounting screws. Operational acoustics come from spindle rotation and actuator movement at 7200 RPM. Power draw follows conventional desktop hard drive profiles for this spindle speed. No special cooling beyond normal case airflow is required.