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XPS 8940, does NOT support dual NVMe SSD drive
I just bought a new XPS 8940 with intel 11700K and RTX 3070, 1TB SSD and 2TB Seagate HDD. I would like to add another NVMe drive for Ubuntu. I placed a PCIe x4 NVMe adapter with WD500G SSD into the PCIe x4 slot, the BIOS can detect it as Mass Storage device, but can not add it into Drive list. So it doesn't work on XPS.
After asking help from Dell support, I got official response: The XPS 8940 does not support PCIe extending NVMe drive!
It means we can only have one NVMe drive in XPS 8940.
What a designer machine!
jlzhou
7 Posts
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May 7th, 2021 09:00
So it is impossible to have more nvme ssd work with i7 CPU and high tier GPU.
1km1km1km
16 Posts
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May 7th, 2021 11:00
Hi jlzhou - please see this thread for more information:
https://www.dell.com/community/XPS-Desktops/XPS-8940-and-Samsung-EVO-970-Plus-Slow-Performance/td-p/7859990
I installed a second SSD in the x4 PCIe slot and it was recognised by Windows - but there were other performance issues I was trying to diagnose.
The 16 + 4 PCIe lanes you are referring to are for direct attach GPU and a M.2 SSD. However, it appears that Dell have not implemented the +4 lanes, at least not on my motherboard. They didn't even exist on Gen 10.
The M.2 slot would appear to be attached via the PCH chip. The limitation is how many PCIe lanes are implemented via the Intel chipset, not the CPU.
And whether Dell officially support it or not is, I guess, up to them.
jlzhou
7 Posts
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May 7th, 2021 19:00
many thanks!
hope Dell can update the bios asap.
x-magic
7 Posts
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November 25th, 2021 18:00
The dual NVMe SSD support is actually broken since BIOS version 2.2.0 (the one that introduces resizable BAR support). I had two NVMe SSDs in the case before that and works OK. But after 2.2.0 BIOS, the system will either freeze at Dell logo, or simply won't POST at all when a secondary NVMe drive is added to any other PCIe slots. Yes, all three slots (x1, x4 which comes from PCH, and even the x16 which is CPU direct) won't work.
Even in the older BIOS versions, there's a glitch that some NVMe SSDs (like the one I'm using with Silicon Motion controller) only works in the on-board M.2 slot but not the x1 or x4 slots.
I believe it's a firmware issue and Dell should be able to fix in a BIOS update. But if a representative says it's not supported, then it means they and that's just disappointing.
x-magic
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December 4th, 2021 04:00
Okey dokey... Thanks for the " ", really apprecated. Would appreciate more if this issue can be actually resolved in a future BIOS update, but I don't give too much hope.
RoHe
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December 9th, 2021 11:00
There's a new BIOS update for the XPS 8940, v2.3.0. So maybe this one fixes the problem...
pstock21
4 Posts
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December 9th, 2021 16:00
I don't know whether it was due to new BIOS 2.3.0, but after some experimentation, I have two nvme ssds working, one in the dedicated m.2 slot, one on a PCIe adapter. They are both Samsung ssds. I have only been able to get this work with SATA set to RAID in BIOS. At this point, I have also had to remove the NVIDIA RTX 3060 from the x16 PCIe slot, too. Gonna try to reinstall it, now that the system at least recognizes both ssds! Will update!
Cheers,
David
pstock21
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December 9th, 2021 17:00
Just a quick update: after reinstalling (but not connecting to a monitor) the NVIDIA gpu and updating the driver, I rebooted and connected NVIDIA gpu to the monitor, and all is working perfectly....for now!
Vic384
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December 9th, 2021 18:00
@pstock21 Just to let you know, Samsung recommnends that SATA operation be set to AHCI in the BIOS. You may wish to change SATA operation in the BIOS if you encounter problems with the RAID setting. To change to AHCI without reinstalling Windows, you need to change the current Windows installation to AHCI by running the following procedure: http://triplescomputers.com/blog/uncategorized/solution-switch-windows-10-from-raidide-to-ahci-operation/
Note that the BIOS change is not made until step 4 of the procedure.
Some Samsung software like Samsung Magician and the Samsung NVMe driver require AHCI, but if don't use that software and are not having problems with RAID then it is up to you to decide if you want to make the change.
pstock21
4 Posts
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December 9th, 2021 19:00
Thanks! But I went through all the permutations, and only in RAID was I able to get both ssds recognized. I realize I am sacrificing Samsung Magician (meh) and the Samsung driver (maybe a loss?), but this is the only way it would work. Moreover, according to CrystalMark, there is no performance difference between the Intel RAID driver and the Samsung NVMe driver. If AHCI would work, I'd prefer it--but it doesn't
x-magic
7 Posts
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December 11th, 2021 03:00
Still the same issue after 2.3.0. No change at all. SATA settings won't make a difference. Need further observation. However I don't have Samsung SSDs to test though.
Freezer75
1 Message
1
January 5th, 2022 08:00
I too have an 8940 and when I try to add a second NVME via an adapter the computer will not boot past the BIOS prompt for a password. I enter my password but Windows won't load, and I can't even enter the BIOS config. Removing the NVME PCIe adapter and the computer works as before. What's most frustrating is I have no other cards/devices in the computer, i.e. no discrete GPU. Assuming the machine has enough PCI lanes then they should be available.
Hopefully Dell can address this in the next BIOS update!
RoHe
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January 5th, 2022 12:00
Time will tell...
acemagic
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February 23rd, 2022 07:00
I have the same issue too. I've been fiddling with this for a month and can't believe that this is a DELL issue. what a poor design for a XPS Machine. I've been using XPS machines for over 15 years and this time they really betrayed their customers. It's called XPS but there's not XPS about it except the price. The case is cheaper and the expandibility of the machine is really lacking.
Note, when I tested on crystal mark, setting to AHCP had better performance vs RAID. It's really ridiculous that it currently supports only 1 nvme ssd even with a PCIex4 card. It's also disappointing enough that it won't support speeds for 980 pro.
RoHe
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February 23rd, 2022 11:00
@acemagic - We don't actually know if this is a Dell or an Intel issue. Intel provides the security fixes that are included in many recent BIOS updates. The XPS 8940 isn't the only PC model having issues with x4 slots after a recent BIOS update, which might suggest it's something Intel did...
What's your 980 Pro speed issue?