Drive comparison
ST18000NM003D vs WD181KFGX
Seagate Exos X20 18TB and Western Digital WD Red Pro 18TB, compared using published manufacturer specifications.
Seagate
Exos X20 18TB
ST18000NM003D
SATA 6 Gb/s · 3.5-inch
$682.58
Amazon US · New listing ↗ASIN B09MWLJ1P5 · as of Sep 12, 2026 11:45 UTC
Full specifications & all listings →
Western Digital
WD Red Pro 18TB
WD181KFGX
SATA 6Gb/s · 3.5-inch
$544.00
Amazon US · Used / renewed listing ↗ASIN B09CN2CBH8 · as of Sep 12, 2026 10:56 UTC
Full specifications & all listings →As an Amazon Associate I earn from qualifying purchases. Match the selected variant, condition and seller terms before ordering.
What differs between these models?
- Interface: ST18000NM003D lists SATA 6 Gb/s; WD181KFGX lists SATA 6Gb/s.
A larger cache, higher RPM or higher advertised sequential speed alone does not establish which drive is better for your workload.
Specifications side by side
| Specification | ST18000NM003D | WD181KFGX |
|---|---|---|
| Manufacturer | Seagate | Western Digital |
| Product family | Exos X20 | WD Red Pro |
| Model number | ST18000NM003D | WD181KFGX |
| Capacity (TB) | 18 | 18 |
| FIPS | No | Not recorded |
| Interface | SATA 6 Gb/s | SATA 6Gb/s |
| Form factor | 3.5-inch | 3.5-inch |
| Manufacturer limited warranty | 5 years (eligible new drives) | 5 years (eligible new drives) |
| RPM | Not recorded | 7200 |
| Recording | Not recorded | CMR |
| Cache (MB) | Not recorded | 512 |
| Workload rating (TB/year) | Not recorded | 550 |
| Physical sector size (bytes) | Not recorded | 4096 |
| Sustained transfer (up to MB/s) | Not recorded | 272 |
Compatibility and buying checks
- Compare new and renewed offers separately. The manufacturer specification does not guarantee the warranty or return policy of a marketplace seller.
Manufacturer sources
ST18000NM003D
Seagate Exos X20 manufacturer specifications ↗
Reviewed 2026-09-07. Published specifications; no independent benchmark or failure-rate claim.
WD181KFGX
Western Digital WD Red Pro manufacturer datasheet ↗
Reviewed 2026-08-21. Published specifications; no independent benchmark or failure-rate claim.