Low 4K read performance on all (3) ssds

Rand__

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Mar 6, 2014
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Anyone any idea why all the drives I tested (3) show significant less 4k read speed than write speed at single queue? I picked 32GB test size, so while disk caching might have some effect it shouldn't be that massive...

This is a quite old win2012 installation, no recent drivers for the 9305-16 the drives are attached to.
CPU load is negligible.
 

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marcoi

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Apr 6, 2013
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Can you take one of the three drives and do some other testing?

1. attach drive directly to port on the MB to test for difference.
2. Attach drive to another pc to test for difference.
3. If the installation OS is VM, can you change host VM to another OS version like w10?
 

T_Minus

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- Did you get these used?
a- If so, did you do a full format, not just a quick one?
b- If not, do one on all used drives I've seen this refresh performance on a # of used SSD drives I would have otherwise returned.
 

Rand__

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Will wipe the disks and attach to an ESXi box to test various OS's.
Had planned to but ESXi psod'ed on the Intel server on boot, probably an issue with the nvdimms I am playing around with.

Will try and provide feedback, thanks
 

Rand__

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So, moved to a vm (still win2012 though), wiped, formated, same issue.
Ran Aja as well, but seq perf is fine.

Atto looks better though, maybe an issue with CDM? Weird though its getting capped at 1G

upload_2019-3-15_0-58-31.png
 

T_Minus

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I have that version of CDM and just hit 3.x\GBs with an Intel NVME. The sequential seem to be right at drive spec on this last test.
I still don't trust it though, as I see 4K Writes way higher than possible when doing 32GB pass.
 

Rand__

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Was searching online a bit and saw many many screenshots of CDM 5 versions exhibiting similar patterns, from cheap consumer drives up to nvme.

Was trying to keep my cdm version at the same level i had it for a while to be able to compare to older results, but...

Will do a fio run later;)
 

Rand__

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I actually have installed 5 and 6 at the same time so not worried about that;)

Just the default tests have changed so not directly comparable any more. Probably configurable though