WD silently replace EFRX with EFZX drives(2-6TB)

WDxxEFZX silently replacing WDxxEFRX?

I am in the looking to replace my WD Red 3TB drives with WD Red Plus 6TB drives (making sure CMR tech is used). Now i noticed that a new WD Red Plus line has entered the market in 2021, namely the EFZX series with 128mb cache instead of 64mb cache currently used by the EFRX series.

If i search WD website for the plus series and end up on the URL below, it seems WD is working on silently replacing the EFRX line with the EFZX line (you can see this by expanding the “recording technology” paragraph on the page.. they only mention the 1 TB as EFRX, the rest is replaced).


Now for my question: EFZX is not listed yet on Synology website, the double cache size appeals to me naturally. Should i hold out for Synology to update the list, should i take a leap of faith due to this being a “Red” nas-specific drive, or should i play it safe and order EFRX drives instead and just be happy with 64mb cache?

These new drives seem to be an upgraded version of their older CMR drives that used the same recording technology. When they silently replaced CMR with SMR drives they had more cache available. Now they have matched the cache size with their SMR drives. In a RAID situation, you will not benefit from this cache since all data is written randomly across many drives. But it is interesting that their speed has been increased from around 150 to 170 MB/s. If you have older drives that are slower you will not benefit from this. But if you have a new NAS then certainly choosing these faster drives would theoretically improve NAS speeds. In the existing setup, the speed will be as fast as the slowest link in the chain. If you connect via 1GbE LAN then you will not notice a speed difference anyway.

If you are wondering if these drives are compatible with Synology then the answer is yes they are.

If you wonder if you can mix them with the older type of drives, the answer is yes you can.


WD101EFBX (10TB)
WD120EFBX (12TB)
WD140EFGX (14TB)


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