WD BLUE 4TB SMR or CMR?

[Zer0]

I am having an OCD dilemma, bought a WD40EZRZ-00GXCB0 with serial WCC7K2HR9Fxx (2 last serial digits not included because of warranty) made on 27 FEB 2020
It's new and I still don't want to open it, because if there is a chance it's SMR I can sell it if it's new and I don't want it.

So this SHOULD be CMR since its "EZRZ" and everybody knows that "EZRZ" are CMR and "EZAZ" are SMR in this instance:
https://nascompares.com/answer/list-of-wd-cmr-and-smr-hard-drives-hdd/
https://hddscan.com/blog/2020/hdd-wd-smr.html

But...what makes me suspicions are the following internet threads, first this reddit post:
https://www.reddit.com/r/zfs/comments/g4fmjl/is_wd_blue_4_tb_smr_or_dmr_anyone_know/
Where somebody claims the difference between two models of WD Blue which are "EZRZ":

WD40EZRZ-00WN9B0 - Giant (C4E in serial number) - 8 heads, PMR
WD40EZRZ-00GXCB0 - APOLLO (С7K in serial number) 6 heads, SMR.

Of course this just might be a mistake, I tracked the original post and it came from Russian forum, so I was searching further and found this website too:
https://electroanswers.com/technolo...#How_do_I_know_if_my_hard_drive_is_SMR_or_CMR

With the claim:
WD40EZRZ-00GXCB0 – APOLLO (С7K in serial number) 6 heads, SMR.
BUT on their list here:
https://www.truenas.com/community/resources/list-of-known-smr-drives.141/
It is not present as SMR.

Then there is a topic from a random member on Linus with the same dilemma:
https://linustechtips.com/status/295061/
And the member assumes that this should be CMR HDD since he has both models of WD Blue and they both have 64mb of cache.

Should I open it, check it with HDD Sentinel for cache size and if it's 64mb, it should be CMR 100% right? Or is this one an isolated case where WD made SMR HDD with 64mb, is that even possible? IS it possible to test it somehow to be 100% sure?

Anyway, I would appreciate if somebody has the same HDD or want to make a philosophical debate out of this case or somebody with extreme knowledge who can shed some light on this dark and tough issue

 

[alphaomega16]

Would inputting the serial number on WD site to warranty check not bring up info on the specific drive you have?

 

[Zer0]

Really a nice suggestion, just did it, this is indeed Apollo with 64MB of cache and with 6 heads as mentioned on various internet threads, can we say that this is a CMR 100% if it has 64MB of cache and is there a chance that it might be SMR because of the above threads I have posted?

 

[alphaomega16]

No clue as to the CMR/SMR status but hoping it might have shed a little more light.

 

[Zer0]

OK to sum up, we have 2 "EZRZ" models of WD Blue in 4TB ("EZAZ" is of course SMR)

WD40EZRZ-00WN9B0 - Giant (C4E in serial number) - 8 heads, PMR (CMR)
WD40EZRZ-00GXCB0 - APOLLO (С7K in serial number) 6 heads, SMR or CMR?

Confusion is based on some internet posts where claims have been made that the second APOLLO model is SMR, because it has less heads (6) which means it has less platters too and it might use SMR because of that (density), but it has 64mb of cache too which would make it CMR since usually SMR HDDs have more cache, which is 256mb from WD.

I have contacted WD asking for confirmation too, really hoping they will respond.

 

[Snapshot]

Given the storm that releasing a second model that was SMR generated when WD did it with the EFRZ, I don't think they would do it again. I think the cache size is the clincher and what would be the point of having two SMR drives of the same capacity.