Verdict

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

WD181KRYZ
WD Gold · 18TB · Enterprise
€942 (€52.34/TB)
WUH721818ALE6L4
WD Ultrastar DC HC550 · 18TB · Enterprise
€1,137 (€63.16/TB)

Value at a glance

Price / TB
WD181KRYZ $32.53
WUH721818ALE6L4 $28.26
Capacity
WD181KRYZ 18 TB
WUH721818ALE6L4 18 TB
Noise (idle)
WD181KRYZ 20 dB
WUH721818ALE6L4 20 dB

Price history · DE, cheapest per day

WD181KRYZ €942 WUH721818ALE6L4 €1,137
zoomed · drag to zoom
€1,137 €768 €399 Jul 2024 Dec 2024 May 2025 Oct 2025 Feb 2026 Jul 2026
WD181KRYZ WUH721818ALE6L4
Capacity 18 TB 18 TB
Recording tech CMR CMR
RAID / NAS safe Yes Yes
Class Enterprise 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) - -
Price / TB $32.53 $28.26
Buy
€942
View at Amazon →
€1,137
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.

WD181KRYZ

No Backblaze failure data for this model.

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

WUH721818ALE6L4

No Backblaze failure data for this model.

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