WD Red Plus 4TB WD40EFPX review

The WD Red Plus WD40EFPX is a 4TB, 3.5-inch SATA hard drive built for NAS enclosures. WD rates it for systems with up to eight bays, a 180TB/year workload and 1,000,000 hours MTBF. It spins at 5,400 rpm, carries a 256MB cache and connects over SATA 6Gb/s.

Those ratings point at home labs, family file servers and small-office boxes rather than larger multi-user storage. If your NAS has eight bays or fewer and mostly holds backups, media and shared documents, the drive is specified for that job.

One detail matters when buying. WD lists two 4TB versions of the Red Plus: the WD40EFPX with 256MB of cache and the WD40EFZZ with 128MB. The figures in this review apply to the WD40EFPX only, so check the model number on the listing before you order.

WD's datasheet lists the WD40EFPX as a CMR drive. For anyone building a RAID array, that is the first thing to confirm, and here it is stated plainly by the manufacturer. There's no SMR question to settle for this model.

The datasheet does not state the recording technology for the WD40EFZZ variant in the research, which is another reason to buy by exact model number.

The headline figures are 1,000,000 hours MTBF and a 180TB/year workload rate. WD also rates the drive for 600,000 load/unload cycles and fewer than one unrecoverable read error per 10^14 bits read. The operating temperature range runs from 0 to 65 °C.

The 180TB/year figure is the one to weigh against your use. A NAS that mostly stores files and runs nightly backups sits comfortably inside it. A box that constantly rewrites large datasets, or serves several heavy users at once, will use more of that allowance. The eight-bay limit sets a similar boundary on enclosure size.

This is where the specification is strongest for home use. At 5,400 rpm, WD rates the drive at 23 dBA idle and 27 dBA when seeking. Power draw is listed at 4.7W during reads and writes, 3.1W at idle and 0.3W in standby or sleep.

Those numbers suit a NAS that runs all day in a home office or living room. With four drives in a small enclosure, the rated active draw totals under 19W for the disks.

WD quotes an internal transfer rate of up to 180MB/s over a SATA 6Gb/s interface. That is a ceiling for the drive itself.

The 256MB cache is listed on the datasheet; WD doesn't publish any further performance figures in the research, such as random I/O rates.

WD covers the drive with a 3-year limited warranty. The datasheet does not mention data recovery services. For a drive intended to run continuously in a NAS, three years is the term to plan replacements around.

The research gathered for this drive includes retailer listings, review summaries and a forum thread on WD Red failure rates, but it does not establish clear recurring owner themes. We have not drawn conclusions about real-world reliability or failure rates from it.

The WD40EFPX's case rests on its stated specification: CMR recording, low rated noise at 23 to 27 dBA, and modest power draw of 4.7W active and 3.1W idle. Its limits are equally clear on paper: 180MB/s, a 180TB/year workload, an eight-bay ceiling and a three-year warranty. For a quiet home or small-office NAS of up to eight bays, it matches what the datasheet promises. For heavier workloads, bigger arrays or longer cover, the ratings fall short.