[SOLVED] Samsung 970 EVO PLUS NVMe M.2 Slow Read Speed

Oct 22, 2021
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Hello, I know that the problem is common, but still didnt find solution.

The speed for my SSD drive is at half the rated speed (~1700MB/s). I am unsure why.

System: ASUS Q325UA (aka UX370UA) notebok + Samsung 970 EVO PLUS
Samsung drivers installed

What I'm doing wrong?

 

Maxxify

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Thank you! Seems you are right. Is there any way to check it for sure?
8 GT/s is per lane, and while it supports 4 lanes these chipsets limit it to 2. 8 GT/s with 128b/130b encoding times two is approximately 1.97 GB/s. There's also ~10% of overhead which gives a maximum of around 1772 MB/s. This matches your result precisely, which is how I knew.

Unfortunately this is a limitation on some models depending on how they implement the chipset. You shouldn't be overly concerned about it, since in most cases you won't be reading or writing to that drive faster than that - since you can't have other sources that could match it on that system. It is possible to write to itself, of course, but these drives have limited SLC caches such that the native TLC speed is actually slower than x2 PCIe 3.0. There are limited cases in the future where the missing sequential reads could be useful - Windows 11, DirectStorage, and games several years from now - but I suspect you wouldn't be playing these games on that machine.
 
Oct 22, 2021
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run hwinfo during that test and look up for your drive temperature during test, it could be overheating, those little things heat up quite a bit without heatsink under load
Drive Temperature : increased from 31 to 44
Drive Temperature2: increased from 36 to 48
 
Oct 22, 2021
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Only using two lanes. This is not uncommon in some laptops, they throttle to two lanes even if it says x4. Some sources refer to this as "GT2" as it typically happens on specific chipsets with integrated GPUs.
Thank you! Seems you are right. Is there any way to check it for sure?
 

Maxxify

Distinguished
Thank you! Seems you are right. Is there any way to check it for sure?
8 GT/s is per lane, and while it supports 4 lanes these chipsets limit it to 2. 8 GT/s with 128b/130b encoding times two is approximately 1.97 GB/s. There's also ~10% of overhead which gives a maximum of around 1772 MB/s. This matches your result precisely, which is how I knew.

Unfortunately this is a limitation on some models depending on how they implement the chipset. You shouldn't be overly concerned about it, since in most cases you won't be reading or writing to that drive faster than that - since you can't have other sources that could match it on that system. It is possible to write to itself, of course, but these drives have limited SLC caches such that the native TLC speed is actually slower than x2 PCIe 3.0. There are limited cases in the future where the missing sequential reads could be useful - Windows 11, DirectStorage, and games several years from now - but I suspect you wouldn't be playing these games on that machine.
 

glnz

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Oct 31, 2009
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To Maxxify and others here - this is an excellent thread for a very similar problem I am having, and I would appreciate your advice. (And maybe the link I am giving below is interesting.)

I have a Dell Optiplex 7010 Mini-Tower with Win 10 Pro 64-bit, an i3 CPU and 16GB RAM. I followed the instructions in the following excellent article to change my hard drive to a Samsung 970 EVO Plus NVMe M.2 and to boot from that M.2, which a 7010 normally cannot do:

https://www.tachytelic.net/2021/12/dell-optiplex-7010-pcie-nvme/

It is working, I am booting from the Samsung NVMe M.2, but I am getting only 1,750 MBps ± in CrystalDiskMark (which is similar to the graphics at the start of this thread), NOT the 3,500 MBps that is shown in the article for a 7010.

Question: if I replace my i3 CPU with an i5 or an i7 that is OK for my motherboard, do you think I will then get the 3,500 MBps throughput that the author of the article gets? Maybe because an i5 or an i7 will provide some PCI-E Gen 3 and not limit my machine to PCI-E Gen 2 only?

Thanks for your thoughts.
 
Question: if I replace my i3 CPU with an i5 or an i7 that is OK for my motherboard, do you think I will then get the 3,500 MBps throughput that the author of the article gets? Maybe because an i5 or an i7 will provide some PCI-E Gen 3 and not limit my machine to PCI-E Gen 2 only?
Start your own topic.
Dell Optiplex 7010 has Q77 chipset.
To get full speed of PCIE 3.0 x4 NVME drive, you need
3rd gen Intel core cpu;​
M.2 PCIE adapter has to be installed in upper PCIE x16 slot (blue color). That's the only slot supporting PCIE 3.0 mode ( and only with 3rd gen cpu).​
 

glnz

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Oct 31, 2009
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SkyNetRising - I just reposted my question at

https://forums.tomshardware.com/threads/nvme-m-2-slow-would-change-to-i7-help.3764072/

and I encourage all here with suggestions to go there and post.

Meanwhile, FYI - yes, my PCIe adapter card with Samsung 970 EVO Plus NVMe M.2 is already plugged into the PCI-E x16 slot (blue color), but I am still getting only 1,750 MBps ±. (If I plug it into the x4 slot, I get about 1,500 MBps.)

Thanks. Hope to see y'all there.
 

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