Which Western Digital Red 4TB NAS hard disk should I buy?

Hardware

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 numberTransfer rateInternal rateCacheRPMRecording TechnologyApprox. DateSpec sheetAmazon AUAmazon US
WD Red WD40EFAX6 Gb/s180 MB/s256 MB5400SMRAug 2020Link[AUD134](https://www.amazon.com.au/Red-4TB-Hard-Drive-WD40EFAX/dp/B083XVY99B?dchild=1&keywords=WD40EFAX&qid=1626346773&s=computers&sr=1-1&linkCode=ll1&tag={{ site.amazonau-referer }}&linkId=656be80cff2750f8ddd8d4de5761b182&language=en_AU&ref_=as_li_ss_tl)[AUD127](https://www.amazon.com/Red-4TB-Internal-Hard-Drive/dp/B083XVY99B?dchild=1&keywords=WD40EFAX&qid=1626346811&sr=8-1&linkCode=ll1&tag={{ site.amazon-referer }}&linkId=e9ee99a46b1b17f3da68631ab866941b&language=en_US&ref_=as_li_ss_tl)
WD Red Plus WD40EFRX6 Gb/s150 MB/s64 MB5400CMRMay 2014LinkAUD165AUD273
WD Red Plus WD40EFZX6 Gb/s175 MB/s128 MB5400CMRJan 2021Link[AUD163](https://www.amazon.com.au/Western-Digital-Plus-Internal-Drive-dp-B08VH8C3WZ/dp/B08VH8C3WZ?&linkCode=ll1&tag={{ site.amazonau-referer }}&linkId=091fd5820c6b65be6affa54ffa69cbaf&language=en_AU&ref_=as_li_ss_tl)[AUD162](https://www.amazon.com/Western-Digital-Plus-Internal-Drive/dp/B08VH8C3WZ?dchild=1&keywords=WD40EFZX&qid=1626346339&sr=8-3&linkCode=ll1&tag={{ site.amazon-referer }}&linkId=ad45eb665e1ff14d9be6be1436675cf9&language=en_US&ref_=as_li_ss_tl)
WD Red Pro WD4003FFBX6 Gb/s217 MB/s256 MB7200CMRSep 2020Link[AUD217](https://www.amazon.com.au/4TB-Red-Pro-Hard-Drive/dp/B07B1WK3N5?dchild=1&keywords=WD4003FFBX&qid=1626346992&s=computers&sr=1-2&linkCode=ll1&tag={{ site.amazonau-referer }}&linkId=2985cb7ab58b9b4b3878ca5d20d28681&language=en_AU&ref_=as_li_ss_tl)[AUD192](https://www.amazon.com/Western-Digital-Red-Hard-Drive/dp/B07B1WK3N5?dchild=1&keywords=WD4003FFBX&qid=1626347021&sr=8-2&linkCode=ll1&tag={{ site.amazon-referer }}&linkId=621ef98c255428085ee9042414976f68&language=en_US&ref_=as_li_ss_tl)

Notes:

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.