XPS 8940, SSD is slow?

Have you seen this youtube? Unfortunately it doesn't mention the test bed used to test this SSD.

Does the SSD have the latest firmware update? Is the latest Intel Rapid Storage driver installed?

According to this, that SSD doesn't have a very high rating...

Thanks for links, the system -drivers and firmware- is updated. The youtube video gives slightly better results, but I think not enough, it seems very strange that a nvme drive could give these results. I think I will try connecting other nvme ssd, I think it may be so slow because of motherboard instead of ssd. I would thank other opinions, it seems very strange nobody has noticed this issue.

@akedna  Dell frequently installs components, like SSDs, from different OEMs, so I guess it depends on how many users have the same Hynix SSD you have and have tested the speed.

The XPS 8940 specs say the M.2 NVMe slot is PCIe Gen3.0 x4 , up to 32 Gbps, if that's of any help. What are the actual specs for your SSD?

Which CPU, how much RAM, and what GPU are in this system? All of those can impact SSD performance.

Read this about possible causes for slow SSD performance and things to check. NOTE: #3 at that site talks about the BIOS AHCI setting being disabled. Dell typically installs Windows on the XPS 8940 with BIOS SATA Mode set to RAID, rather than AHCI, but you can't just change that setting to AHCI in BIOS directly. You have to follow specific steps to make the change, otherwise Win 10 can become unbootable and you'd probably end up having to do a clean install. So just check that BIOS setting, but don't change it for now. We can give you the steps to do this properly, if BIOS is actually set to RAID and you want to try AHCI...

EDITED

Hi @RoHe, I will test with other nvme drives, thanks again for tips. But I'm pretty sure ahci mode doesn't affect nvme, it is only for sata.

@akedna What you wrote about AHCI being only for SATA may be true, but I know that loading the NVMe driver for Samsung PCIe NVMe SSDs requires AHCI. 

humm, thanks @Vic384 , it seems true, from other post:

Many Dell Systems come with NVMe drives being controlled by the Intel SATA/PCIe controller. For the M.2 slot to function in that manner, the SATA controller in the Bios needs to be set to RAID.

You can change the controller using a special procedure but the performance with the newer Intel SATA/PCIe Premium controller is almost as good as using the NVMe controller.

@akedna  Yes, as @Vic384 said, we've had experience with Samsung SSDs that don't play nicely with BIOS set to RAID. And you're seeing performance issues with this Hynix SSD, and BIOS is likely set to RAID.

It won't hurt to change BIOS to AHCI, as long as you do it properly. And you can always go back to RAID if AHCI makes performance even worse than with RAID, as long as you do it properly.

You might try contacting Hynix tech support so see if they have anything to say about RAID vs AHCI or about the performance of your SSD...

Your PC, your decisions...

Also tried changing changing the BIOS to AHCI and no change to the SSD speed

I have the same problem  brand new XPS 8940  came with Samsung PM9A1 (capable of 7000 MB/s) and I'm getting 900 MB/s using Crystal Disk Mark and the same using PerformanceTest.  3 Pro Support people could not help.  It's a newly designed mother board.  Maybe that's the problem.  Hopefully Dell will respond as I seen 3 or 4 of these identical threads for the 8940.

@jc_using_dell, @akedna  What CPU (include Generation), how much RAM and what GPU do you each have in your XPS 8940?

I've pinged my Dell tech contacts and your specs may provide some useful info...

Already gave them that link too. 

@jc_using_dell  Thanks.

BTW: What version of BIOS is installed? If you don't know, click Start>Run and type in msinfo32.exe and click OK.  When that opens, click System Summary in left pane and scroll down right pane to BIOS Version/Date.

@jc_using_dell  - I pointed my Dell tech contacts at this thread so they can see your specs and what @akedna posts.

I'll let post back if I hear anything, but it may take a while to get things reviewed and tested...

system is:

xps8940   11700K processor,  Nvidia 3070,  samsung NVMe PM9A1,  64 GB memory,  Win 10 pro,  Killer WiFi