Verdict

For a NAS or any RAID array, the HDWR480 is the clear pick - it's a CMR drive, while the ST8000DM004 uses SMR recording, which is not recommended for RAID. Only consider the ST8000DM004 for single-drive or archival use.

HDWR480 ST8000DM004
Capacity 8 TB 8 TB
Recording tech CMR SMR
RAID / NAS safe Yes No
Class Desktop Desktop
Spindle speed 7200 RPM 5400 RPM
Cache 256 MB 256 MB
Noise (idle) 20 dB 22 dB
Fill Air Air
Interface SATA SATA
Failure rate (AFR) - -
Price / TB - $31.25

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB shows once live prices are wired.