In WD Red plus family, there are multiple variants in 4TB, 6TB, 8TB, 14TBcapacity. They are all CMR drives being RED plus but with different hardware specifications.
Annual work load, warranty and MTBF etc are all the same for these models , except RPM and Cache ( and Internal transfer rates which are are directly related to RPM)
WD80EFBX vs WD80EFZZ
|Internal Transfer Rates||210 MB/s||185 MB/s|
WD80EFZZ sells at a lower price point compared to WD80EFBX due to lower hardware specifications.
WD60EFPX vs WD60EFZX
There is minor difference in the RPM ( 5640 RPM is a new class of RMPs with WD) so the transfer rates on both the drives are almost same.
|Internal Transfer Rates||180 MB/s||185 MB/s|
WD140EFGX vs WD140EFFX
The only difference between the 2 drives is that WD140EFFX may be seen as a 5400 RPM drive by the host even though its a 7200 RPM drive. WD140EFGX will be seen correctly as 7200 RPM. All other hardware specifications are the same.