Western Digital
Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD (WD40EFRX)
Status: Western Digital 4TB WD Red Plus NAS Internal…: Unavailable on Amazon as of . SpecPicks has no in-stock listing with matching specs on file; the search below lists current offers. eBay sellers may still list this model new or used.
Bottom line: The Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD: CMR recording, not SMR, so ZFS and RAID rebuilds finish without shingled write stalls; main trade-off: 3-year warranty trails the 5-year coverage on WD Red Pro and rival NAS lines.
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Currently unavailable on Amazon. Not the same product — 3 in-stock alternatives:
Similar: Western Digital 2TB WD Red Plus NAS Internal… — $209.00 on Amazon as of 2026-10-20 22:15 UTC (price may vary).
Similar: Seagate 4TB IronWolf NAS SATA Hard Drive 6Gb/s… — $184.95 on Amazon as of 2026-10-21 04:16 UTC (price may vary).
Similar: Western Digital 12TB WD Red Plus NAS Internal… — $697.10 on Amazon as of 2026-10-20 22:15 UTC (price may vary).
Pros & Cons
Pros
- ✓ CMR recording, not SMR, so ZFS and RAID rebuilds finish without shingled write stalls
- ✓ Rated for 180TB/yr workload, well above typical desktop drive ratings
- ✓ NASware firmware prevents array dropouts during error recovery
- ✓ 5400RPM class runs cooler and quieter than 7200RPM drives in packed bays
Cons
- ✗ 3-year warranty trails the 5-year coverage on WD Red Pro and rival NAS lines
- ✗ 5400RPM class limits single-drive throughput versus 7200RPM alternatives
- ✗ 64MB cache is small next to the 256MB+ on newer NAS drives
- ✗ Officially validated only to 8 bays, so larger arrays fall outside spec
Manufacturer description
The WD Red Plus WD40EFRX gives you 4TB of CMR storage built specifically for always-on NAS duty, not repurposed desktop use. Western Digital rates this drive for 24x7 operation in small and medium business enclosures, with support for bays counts up to eight and a workload rating of up to 180TB per year. That workload figure matters if you run ZFS scrubs, parity rebuilds, or nightly backup jobs, because consumer desktop drives are typically rated far lower. The 5400RPM performance class keeps heat and acoustics down in a multi-bay chassis, while 64MB of cache and a SATA 6Gb/s interface…
SpecPicks Verdict
SpecPicks scored Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD using a rating × review-volume × price-fit model applied to published specs and reviews across the nas & home servers category. Western Digital's nas & home servers lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.
Common buyer scenarios for nas & home servers of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.
Frequently Asked Questions
Is the WD40EFRX CMR or SMR?
CMR. Western Digital renamed this model WD Red Plus specifically to separate it from the SMR-based WD Red line. If the box says WD Red, confirm the model number reads WD40EFRX.
How many drive bays does this support?
Western Digital builds and tests WD Red Plus for NAS enclosures with up to 8 bays. The family spans 1TB to 14TB capacities, so you can mix sizes across an array.
Can it handle 24/7 operation?
Yes. It is rated for 24x7 environments in small and medium business NAS systems, with a workload rate of up to 180TB per year measured as total data transferred to or from the drive.
Does it work with ZFS and RAID rebuilds?
Yes. Western Digital calls out ZFS and other file systems for array rebuilding, and the CMR recording plus NASware firmware are what make long rebuilds complete reliably.
What warranty comes with this drive?
A 3-year limited warranty. Registration and claim terms are handled by Western Digital, so check the current product listing for details before you buy.
Key Features
- Available in capacities ranging from 1-14TB with support for up to 8 bays
- 5400RPM performance class
- Supports up to 180 TB/yr workload rate*| * Workload Rate is defined as the amount of user data transferred to or from the hard drive. Workload Rate is annualized (TB transferred ✕ (8760 / recorded power-on hours))
- NASware firmware for compatibility
- Small or medium business NAS systems in a 24x7 environment
- 3-year limited warranty
Full Specifications
| Brand | Western Digital |
|---|---|
| Color | Red |
| Model Name | WD40EFRX |
| Unit Count | 1 Count |
| Form Factor | 3.5-inch |
| Media Speed | 5200 rpm |
| Model Number | WD40EFRX |
| Built-In Media | Hard Drive |
| Hard-Drive Size | 4 TB |
| Mfr Part Number | WD40EFRX |
| Number of Items | 1 |
| Special Feature | Western Digital 4TB SATA |
| Item Part Number | WD40EFRX |
| Hardware Platform | PC; Mac |
| Installation Type | Internal Hard Drive |
| Compatible Devices | NAS systems |
| Data Transfer Rate | 600 megabits_per_second |
| Enclosure Material | Aluminum |
| Additional Features | Western Digital 4TB SATA |
| Hard Disk Interface | Serial ATA-600 |
| Full listing title | Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, CMR, 64 MB Cache, 3.5" - WD40EFRX |
Ready to buy?
Amazon shows no buyable offer for Western Digital 4TB WD Red Plus NAS Internal… at the last check. A similar in-stock product is Western Digital 2TB WD Red Plus NAS Internal…. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
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