Western Digital · NAS
WD4003FFBX
WD Red Pro 4TB
SATA 6Gb/s · 3.5-inch · CMR
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View on Amazon US ↗Used / renewed listing · ASIN B07SKWFDY2
All 2 matched listings ↓As an Amazon Associate I earn from qualifying purchases.The Western Digital WD4003FFBX is a 4TB WD Red Pro hard drive for NAS storage, using SATA 6Gb/s in a 3.5-inch form factor.
Manufacturer specifications
| Model number | WD4003FFBX |
|---|---|
| Nominal capacity | 4 TB · 4000 GB |
| RPM | 7200 |
| Interface | SATA 6Gb/s |
| Recording | CMR |
| Cache (MB) | 256 |
| Form factor | 3.5-inch |
| Workload rating (TB/year) | 550 |
| Physical sector size (bytes) | 4096 |
| Manufacturer limited warranty | 5 years (eligible new drives) |
| Sustained transfer (up to MB/s) | 217 |
Source: Western Digital WD Red Pro manufacturer datasheet. Reviewed 2026-08-21. Published specifications, not our benchmark results.
What the specifications mean
- CMR recording is specified for this exact model. Check enclosure support and workload limits before installing it in an array.
- Up to 217 MB/s sustained transfer, as specified by the manufacturer. This is not a measured game-loading or random-I/O result.
- 550 TB/year workload rating. This is a workload limit, not a promise of drive lifespan or a backup guarantee.
Before ordering
Match WD4003FFBX, 4TB and SATA 6Gb/s against the selected offer. Check your system’s exact-model compatibility list and the seller’s warranty and return terms.
Amazon US listings
Exact model matches on Amazon.com. A verified ASIN identifies the product; it does not guarantee current stock. Check the selected variant, condition and seller.
Amazon US · ASIN B07SKWFDY2
Amazon US · ASIN B07SKWFDY2
Same-capacity alternatives with Amazon US links
These models share the drive type, interface class and capacity. Compare their specifications and your system requirements before choosing a replacement.
Seagate · IronWolf
ST4000VN006
4TB · SATA 6 Gb/s · CMR
Compare with WD4003FFBX →View on Amazon US ↗ASIN B09NHV3CK9 · Check price and conditionSeagate · IronWolf
ST4000VN008
4TB · SATA 6 Gb/s · CMR
Compare with WD4003FFBX →View on Amazon US ↗ASIN B01LOOJBQY · Check price and conditionSeagate · IronWolf Pro
ST4000NE001
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Compare with WD4003FFBX →View on Amazon US ↗ASIN B07SY4T6F5 · Check price and conditionWD4003FFBX questions answered
Is WD4003FFBX CMR or SMR?
The manufacturer lists CMR recording for WD4003FFBX. Other models and capacities in the same family can differ.
What connection does WD4003FFBX need?
WD4003FFBX uses SATA 6Gb/s and a 3.5-inch form factor. Match both with the computer, controller or enclosure. An M.2 slot, 2.5-inch bay and 3.5-inch bay are not interchangeable.
How much usable space does WD4003FFBX provide?
Its nominal capacity is 4000 GB, approximately 3725.3 GiB before formatting. The filesystem, reserved space and any RAID redundancy reduce usable capacity further.
What warranty is listed for WD4003FFBX?
Manufacturer specification: 5 years (eligible new drives). A renewed, used, OEM or imported offer can have different coverage. Check the serial number and seller terms before buying.