Western Digital · NAS
WD40EFPX
WD Red Plus 4TB
SATA 6 Gb/s · 3.5-inch · CMR
Exact Amazon US product
$231.23
View on Amazon US ↗New listing · ASIN B0BDXSK2K7
Price as of Sep 12, 2026 11:44 UTC
The Western Digital WD40EFPX is a 4TB WD Red Plus hard drive for NAS storage, using SATA 6 Gb/s in a 3.5-inch form factor.
Manufacturer specifications
| Model number | WD40EFPX |
|---|---|
| Nominal capacity | 4 TB · 4000 GB |
| RPM | 5400 |
| NAS bays | Up to 8 |
| Interface | SATA 6 Gb/s |
| Recording | CMR |
| Cache (MB) | 256 |
| Form factor | 3.5-inch |
| Workload rating (TB/year) | 180 |
| Manufacturer limited warranty | 3 years (eligible new drives) |
Source: WD Red Plus datasheet, September 2025, pages 2. Reviewed 2026-09-07. 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.
- 180 TB/year workload rating. This is a workload limit, not a promise of drive lifespan or a backup guarantee.
Before ordering
Match WD40EFPX, 4TB and SATA 6 Gb/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 B0BDXSK2K7
$231.23 · as of Sep 12, 2026 11:44 UTC
Amazon US · ASIN B0BDXSK2K7
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 WD40EFPX →View on Amazon US ↗ASIN B09NHV3CK9 · Check price and conditionSeagate · IronWolf
ST4000VN008
4TB · SATA 6 Gb/s · CMR
Compare with WD40EFPX →View on Amazon US ↗ASIN B01LOOJBQY · Check price and conditionSeagate · IronWolf Pro
ST4000NE001
4TB · SATA 6 Gb/s · CMR
Compare with WD40EFPX →View on Amazon US ↗ASIN B07SY4T6F5 · Check price and conditionWD40EFPX questions answered
Is WD40EFPX CMR or SMR?
The manufacturer lists CMR recording for WD40EFPX. Other models and capacities in the same family can differ.
What connection does WD40EFPX need?
WD40EFPX uses SATA 6 Gb/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 WD40EFPX 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 WD40EFPX?
Manufacturer specification: 3 years (eligible new drives). A renewed, used, OEM or imported offer can have different coverage. Check the serial number and seller terms before buying.