Drive comparison
ST12000NM000J vs WD121KFBX
Seagate Exos X18 12TB and Western Digital WD Red Pro 12TB, compared using published manufacturer specifications.
Seagate
Exos X18 12TB
ST12000NM000J
SATA 6 Gb/s · 3.5-inch
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Western Digital
WD Red Pro 12TB
WD121KFBX
SATA 6Gb/s · 3.5-inch
$698.00
Amazon US · New listing ↗ASIN B07RTMPWD8 · as of Sep 12, 2026 11:48 UTC
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What differs between these models?
- Interface: ST12000NM000J lists SATA 6 Gb/s; WD121KFBX lists SATA 6Gb/s.
- Sustained transfer (up to MB/s): ST12000NM000J lists 270; WD121KFBX lists 240.
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 | ST12000NM000J | WD121KFBX |
|---|---|---|
| Manufacturer | Seagate | Western Digital |
| Product family | Exos X18 | WD Red Pro |
| Model number | ST12000NM000J | WD121KFBX |
| Capacity (TB) | 12 | 12 |
| RPM | 7200 | 7200 |
| Interface | SATA 6 Gb/s | SATA 6Gb/s |
| Cache (MB) | 256 | 256 |
| Form factor | 3.5-inch | 3.5-inch |
| Average idle power (W) | 4.4 | Not recorded |
| Power-on hours per year | 8760 | Not recorded |
| Manufacturer limited warranty | 5 years (eligible new drives) | 5 years (eligible new drives) |
| Sustained transfer (up to MB/s) | 270 | 240 |
| Recording | Not recorded | CMR |
| Workload rating (TB/year) | Not recorded | 550 |
| Physical sector size (bytes) | Not recorded | 4096 |
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
ST12000NM000J
Seagate Exos X18 manufacturer specifications ↗ · pages 3
Reviewed 2026-09-07. Published specifications; no independent benchmark or failure-rate claim.
WD121KFBX
Western Digital WD Red Pro manufacturer datasheet ↗
Reviewed 2026-08-21. Published specifications; no independent benchmark or failure-rate claim.