Back in April I mentioned purchasing two Western Digital Red NAS 4TB hard disk (Model WD40EFRX).

I’m thinking about buying another one or two similar drives, but on closer inspection I noticed that there’s a few different WD Red 4TB drives to choose from.

Western Digital Red 4TB SATA Drives

Model number Transfer rate Internal rate Cache RPM Recording Technology Approx. Date Spec sheet Amazon AU Amazon US
WD Red WD40EFAX 6 Gb/s 180 MB/s 256 MB 5400 SMR Aug 2020 Link AUD134 AUD127
WD Red Plus WD40EFRX 6 Gb/s 150 MB/s 64 MB 5400 CMR May 2014 Link AUD165 AUD273
WD Red Plus WD40EFZX 6 Gb/s 175 MB/s 128 MB 5400 CMR Jan 2021 Link AUD163 AUD162
WD Red Pro WD4003FFBX 6 Gb/s 217 MB/s 256 MB 7200 CMR Sep 2020 Link AUD217 AUD192


  • Prices were at 15th July 2021, and were captured in Australian Dollars (your currency may differ). Click through to the links to get the latest price. Most Amazon links above are affiliate links.
  • Dates are from the oldest specification sheets I’ve found for that model.
  • Recording technology: SMR - Shingled Magnetic Recording, CMR - Conventional Magnetic Recording. More info

I also found a useful overview of the Red, Red Plus and Red Pro lines.

Looking at that data it does look like for the ‘Pro’ line the WD40EFZX represents better value, but for the home enthusiast the WD40EFAX seems reasonable.