M.2 NVMe speed only 400 MBps

[Rayqusa]

hi, I am using jun loader 1.04 and DS918+

my spec is

intel gold G5420

Mainboard Acer veriton M660

DDR4 4GB 

 

I have installed M.2 samsung NVMe 128GB as volume2.

I tried benchmarking with dd bs=1M count=256 if=/dev/zero of=/volumeX/share/testx conv=fdatasync only got score 400MBps

my hdd got score 40 MBps.

my NVMe on windows easily get 1000 MBps

whats wrong with my configuration?

 

usually i use my NVMe as cache, but it seem slow. then I test it

 

thank you for your answer

[flyride]

Not a typical configuration to have NVMe as a regular DSM volume.  How did you set it up?  It might have an impact.

 

You did not say what model your SSD was. Generally, write performance on low-capacity Samsung models is not great.  PM961 is a typical 128GB unit and its spec is "up to" 600MBps sequential write which is a raw value, and the score you are citing is full throughput including filesystem overhead etc.

 

Also all consumer Samsung drives have TLC with SLC/MLC cache so once that internal cache fills up they slow down on writes a lot.

 

I suspect Windows is lying to you with 1GBps write.  But post more info about what you have if you want

Edited February 7, 2022 by flyride

[Rayqusa]

I just tried unmount my nvme cache. Then go to storage pool. Then I can create new pool and choose my nvme 
 

Then I create volume. 
The nvme was mounted on /volume2. 
 

Yes I know usually nvme can't be mounted as general volume on ds918. But it happen
 

I might edit etc.default before I have nvme to enable mounting nvme. I read the tutorial here. 
 

But I don't know that method working or not because that time I have not nvme disk yet. 

 

My nvme is samsung mz hpu128t/000

Edited February 9, 2022 by Rayqusa
Add picture and nvme model

[flyride]

Your reported write performance (the 400MBps test result) is consistent with Tweaktown's review of this model in 128GB.

 

https://www.tweaktown.com/reviews/6589/samsung-xp941-128gb-pcie-ssd-review/index.html

[Rayqusa]

I think that is read speed. it is write? thank you then

[nadiva]

you provided write test result, and included the advertised speed in the screenshot. and it matches. nothing to write about here:)

"my NVMe on windows easily get 1000 MBps" it means not a properly executed benchmark. No drive will be faster than specified, even if it's shortly masked by cache or something like ASUS RAM disk. NVMe drives can have speed of 0.5GBs to 7GBs. You drive is too old to be shining today. 951 successor model is 2.5x faster, 980 is another 2.5x faster despite small capacity.

[polanskiman]

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