WD Red Pro 4TB WD4005FFBX review

The WD Red Pro 4TB (WD4005FFBX) is a NAS hard drive from Western Digital. It has 4TB of capacity, 256MB of cache and a 7200 RPM spindle. WD rates it for RAID-optimised NAS systems with an unlimited number of bays. It gives no numeric bay count, so the practical limit is whatever your enclosure supports.

The sections below cover what the specifications say.

This is the drive's strongest area. WD lists an MTBF of 2.5 million hours and a workload rating of 550TB per year. Those figures describe a drive meant for sustained, multi-user use rather than occasional file storage.

The unlimited-bay rating adds to that. A drive rated for RAID-optimised systems of any size is a sensible fit for a larger array, where several disks run together and one slow or failing member affects the rest.

The research holds no failure-rate data, so the MTBF and workload figures are WD's ratings, not field results.

The spec table lists CMR recording, and WD rates the drive for RAID-optimised NAS systems.

WD rates the sustained transfer rate at up to 217MB/s. The 256MB cache is listed alongside it. That is a manufacturer figure, an "up to" number, and real transfers will vary with the workload and the NAS. The research gives no independent throughput measurements for this exact model. Reviews of older 4TB Red Pro drives with a 64MB cache exist, but they cover different hardware, so they don't tell us how this one behaves.

At 7200 RPM, this is the area to weigh if the NAS sits in a quiet room. The research lists no noise level, idle power or operating power for the drive. So there is nothing to say about how loud or warm it runs beyond the spindle speed itself. If your NAS sits in a bedroom, living room or cupboard with little airflow, look for noise and power figures from WD before buying.

WD gives a five-year limited warranty. That sits alongside the 550TB/year workload rating.

Data recovery is not included. WD sells a separate Data Recovery Protection plan. WD's UK page for the 10TB model says that using the drive in a RAID configuration or device voids that plan. That wording comes from the 10TB page, and the terms for the 4TB model may differ. Check the plan's terms before you count on it. If you buy this drive for RAID, assume you are covered by the warranty and your own backups, not by a recovery service.

The research holds aggregate ratings, not written comments. Amazon UK shows 4.2 out of 5 from 72 ratings. Micro Center shows 4.69 from 16 reviews. Best Buy shows 4 out of 5 from 3 reviews. The ratings are positive, but the sample sizes are small, and they say nothing about specific strengths or faults such as noise or failure rates.

With CMR recording, a 550TB/year workload rating, a 5-year warranty and a rating for RAID-optimised NAS systems, this drive suits a multi-bay NAS or RAID array that will see regular use. WD's rated sustained rate is up to 217MB/s.

It suits quiet-room setups less well. The 7200 RPM speed is the spec to weigh there, and WD's noise figures are absent from the research. Buyers who want data recovery bundled in should also note that it is a separate, conditional plan.