Samsung SSD 950 PRO M.2 READ SPEED PROBLEM

Janillo

Commendable
Oct 1, 2016
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1,510
I have a windows 7 x64 system with an ASUS P8Z68-V/GEN3 motherboard. I installed a samsung SSD 950 PRO into the second PCIE 3.0 x16 slot (the first one is used by the graphics card) by using the following M.2 PCIe adapter:

http://www.lycom.com.tw/DT-120.htm

I installed the NVMe driver and the system recognized the drive. I cloned my windows 7 to the SSD drive, I changed the boot order in the BIOS, and all seemed to work fine. However, when I first boot the system, it didn't look like so fast as I was expecting. When I checked the drive performance with the Samsung Magician, that is what I got:

Reading speed: 722 Mb/s (3-4 times lower than expected)
Writting speed: 1542 Mb/s (just the one expected)

Why do I get this results? Perfect in writting but very low in reading. What is missing?

I checked on the motherboard specifications that this expansion slot is not bandwidth shared:

https://www.asus.com/Motherboards/P8Z68VGEN3/specifications/

Anyone can help?
Thanks
 
Solution


I think the bottleneck is your motherboard, not OS.

waltercarroll

Commendable
Sep 21, 2016
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The problem is you are running an older motherboard chipset that doesn't take full advantage of the PCI express lanes. You need a motherboard that has the PCIe Gen 3 X4 M.2 that will utilize the X4 on the PCIe lanes. For example, the Gigabyte GA-Z170X-Gaming 7-EU. This has the Z170 chipset and supports the Skylake CPU. Also, if you are going with SLI the most you an support two video cards running at 8x. And the final piece is that you need to ensure to run Windows 7. You can use the Samsung 950 Pro NVMe drive(s) and the boot drive. Windows 7 takes full advantage of the faster PCI channels.
 

Janillo

Commendable
Oct 1, 2016
4
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1,510
Thank you for your answers. I don't know how to upload images, sorry :(

In the Magician it says :

Link Speed Cur: 4Gbps, Max : 8Gbps
Link Width Cur: x4, Max :x4
Bandwidth Cur: 16Gbps, Max; 32Gbps

The PCIe I'm using is gen3.0 x16 as you can see by these data. This bandwidth should be enough to achieve maximum speed, right?

Good news are that with CrystalDiskMark I get
Reading speed: 1699 Mb/s
Writting speed: 1538 Mb/s

Better results but still not as high as expected. Are you sure it is because of the chipset?
This is the maximum I can get with the actual hardware or could the windows OS have anything to do as well?
Thanks again!

 

Palorim12

Distinguished


See how it says your current Link Speed is 4Gbps and your Link Width is x4. Its literally multiplication. 8Gbps x 4 = 16Gbps, which is around 1600Mbps, give or take. Which is the speed Crystal Disk Mark is saying you're getting.
 

Palorim12

Distinguished


This is how i always saw it:

SATA I - 1.5Gbps = ~150MB/s
SATA II - 3Gbps = ~300MB/s
SATA III - 6Gbps = ~550MB/s
SATA Express - 10Gbps = ~1000MB/s
You - 16gbps = ~1600MB/s
 

Janillo

Commendable
Oct 1, 2016
4
0
1,510
Thank you Palorim!

So the difference comes from bits vs bytes x8 factor, right? That easy! :)

Do you think upgrading to windows 8 or windows 10 will improve my results? Is it worthy to do it? Or just wait for a computer upgrade, let's say in a year, and install a new motherboard with m.2 ports?

Thanks in advance
 

Palorim12

Distinguished


I think the bottleneck is your motherboard, not OS.
 
Solution