Verdict

For a NAS or any RAID array, the ST2000NT001 is the clear pick - it's a CMR drive, while the ST2000DM008 uses SMR recording, which is not recommended for RAID. Only consider the ST2000DM008 for single-drive or archival use.

ST2000DM008 ST2000NT001
Capacity 2 TB 2 TB
Recording tech SMR CMR
RAID / NAS safe No Yes
Class Desktop NAS-Pro
Spindle speed 7200 RPM 7200 RPM
Cache 256 MB 256 MB
Noise (idle) 22 dB 28 dB
Fill Air Air
Interface SATA SATA
Failure rate (AFR) - -
Price / TB $54.92 $95.25

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.