Driver bug on Windows Server 2016 with Samsung NVMe for SM951

[rcarlos243]

The Samsung NVMe driver for SM951 NVMe is not working properly on Windows Server 2016 version 1607 (OS Build 14393.1066).

I tried Samsung NVMe driver version 1.1, 2.1, and the latest 2.2 but they do not work properly.

The write IOPS is way too low (it should be XX,XXX IOPS but I only get XXX IOPS).

I tried the SM951 NVMe on Windows 10 and it works perfectly (I get the expected write IOPS). I also tried Samsung 950 Pro on Windows Server 2016 and it works perfectly.

The SM951 does not deliver the proper IOPS under Windows Server 2016 due to Samsung NVMe driver not working properly (Poor write IOPS performance).

I tried contacting Samsung http://www.samsung.com/semiconductor/about-us/business-overview/

I get a "The specified URL cannot be found." once I submitted a question form.


Samsung SM951 NVMe under Windows Server 2016

Samsung SM951 NVMe under Windows 10

Samsung 950 Pro under Windows Server 2016

 

[XavierMace]

Have you tried using the Win10 driver on 2016?

 

[rcarlos243]

Have you tried using the Win10 driver on 2016?

There is only 1 driver available on Samsung Website.

 

[XavierMace]

So 2016 is using the same driver as Win10?

 

[BonzaiDuck]

The Server 2016 version should incorporate a native NVMe driver. Have you tried benchmarking the rig with that driver?

 

[Micrornd]

So 2016 is using the same driver as Win10?

Samsung doesn't say that the driver does support Server 2016, although any properly written Windows 10 driver will, unless it is intentionally/specifically locked out.

 

[rcarlos243]

The Server 2016 version should incorporate a native NVMe driver. Have you tried benchmarking the rig with that driver?

The Microsoft NVMe driver gives me the exact same poor result with SM951 NVMe and 950 PRO under Windows 10 and Windows Server 2016.

I also just noticed that write caching policy is disabled on device manager by default for SM951 NVMe under Windows Server 2016 (950 PRO under Windows Server 2016 has it enabled and SM951 NVMe under Windows 10 has it also enabled).
I enabled the write caching policy for the SM951 NVMe under Windows Server 2016, but I am still only getting 1/2 the expected write performance.

I also noticed that every time I reboot or shutdown the system unit, the write caching policy for the SM951 NVMe under Windows Server 2016 automatically gets disable for some reason.

 

[Micrornd]

rcarlos243 -

How do you have write-caching of the drive set in Server 2016 ?
It will make a difference.

Edit - I was typing as you were posting.
Have you tried changing the write-cache buffer flushing setting?

 

[rcarlos243]

rcarlos243 -

How do you have write-caching of the drive set in Server 2016 ?
It will make a difference.

What do you mean? Are you making a statement or asking a question?

If you are asking a question see my latest post above and the original post and that will answer your question.

 

[Micrornd]

I was typing as you were posting.
Have you tried changing the write-cache buffer flushing setting?

 

[rcarlos243]

I was typing as you were posting.
Have you tried changing the write-cache buffer flushing setting?

Yes and it made 0 difference in performance when I did the same tests.

 

[Micrornd]

Is the 951 in the top slot?
And there any drives connected to the SATA ports 0 or 1?
I ask because as I read/interpret the board's manual, if the above is true, the drives performance will be reduced.
(See the chart on p32 of the manual)
It looks as though the lower slot is best for full speed usage of the drive with less conflicts.

 

[rcarlos243]

Is the 951 in the top slot?
And there any drives connected to the SATA ports 0 or 1?
I ask because as I read/interpret the board's manual, if the above is true, the drives performance will be reduced.
(See the chart on p32 of the manual)
It looks as though the lower slot is best for full speed usage of the drive with less conflicts.

Bandwidth is not an issue as I get the full expected speed under Windows 10 on SM951 NVMe.

 

[Micrornd]

The results you posted for Windows 10 were from a different board and cpu, could you post the results for Windows 10 on that board and cpu just for comparison?