Verdict

These are closely matched NAS drives of the same capacity - decide on price and warranty. Check the live $/TB above.

WD161KFGX
WD Red Pro · 16TB · NAS-Pro
£654 (£40.87/TB)
WUH721816ALE6Lx
WD Ultrastar DC HC550 · 16TB · Enterprise
£475 (£29.69/TB)

Value at a glance

Price / TB
WD161KFGX $42.01
WUH721816ALE6Lx $37.70
Capacity
WD161KFGX 16 TB
WUH721816ALE6Lx 16 TB
Noise (idle)
WD161KFGX 20 dB
WUH721816ALE6Lx 20 dB

Price history · UK, cheapest per day

WD161KFGX £654 WUH721816ALE6Lx £475
zoomed · drag to zoom
£1,023 £652 £280 Jul 2024 Dec 2024 May 2025 Oct 2025 Feb 2026 Jul 2026
WD161KFGX WUH721816ALE6Lx
Capacity 16 TB 16 TB
Recording tech CMR CMR
RAID / NAS safe Yes Yes
Class NAS-Pro Enterprise
Spindle speed 7200 RPM 7200 RPM
Cache 512 MB 512 MB
Noise (idle) 20 dB 20 dB
Fill Helium Helium
Interface SATA SATA
Failure rate (AFR) - 0.88%
Price / TB $42.01 $37.70
Buy
£654
View at Amazon →
£475
View at Amazon →

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB uses the cheapest live price. Buy links are Amazon affiliate.

WD161KFGX

No Backblaze failure data for this model.

5yr warranty · 300 TB/yr rated · 1,000,000h MTBF

WUH721816ALE6Lx

0.88% AFR vs 1.34% fleet avg

95% CI 0.78-0.98%

29,795 drives · ~36,808 drive-years · 323 failures · Backblaze thru Q1 2026

5yr warranty · 550 TB/yr rated · 2,500,000h MTBF