Precision Fixed Workstations

Last reply by 04-22-2022 Unsolved
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1 Copper
1 Copper

Precision 5820 x Dell Ultra-Speed Drive Quad NVMe M.2 PCIe x16 Card

Hello team, 

As the subject states I have a Dell Precision 5820 which supports PCI-e bifurcation (as far as I know)

I also have a Dell Ultra-Speed Drive Quad NVMe M.2 PCIe x16 Card.

The card has 4x1TB Samsung 980 V-NAND SSD M.2

However, I never get to see all 4 drives. There are combinations I can do (PCI-e slots 0,3 / 0,2) that show me 2 individual drives but when it's 4 drives installed, I never get to see 4 drives. At most 1 or 2 (with 4 drives installed).

How can I get BIOS or Windows to see all 4 drives? I didn't see anything specific in BIOS or Windows. 
Preferably I could configure this as JBOD so I can raid them, but as of right now, I can't do much if I don't see all drives.

No pending Windows/BIOS/Driver updates as of this posting. 

Please advise.

System Info:

Win10 Pro Version 10.0.19044 Build 19044
BIOS Version/Date Dell Inc. 2.14.0, 12/16/2021
Installed Physical Memory (RAM) 64.0 GB

Reply (1)
4 Tellurium


so, there are various configurations for the 5820, based on the cpu used


Card slots

PCIe Gen 3
Slot configuration for Xeon W and Core i9X CPUs
  • 2 PCIe x 16
  • 1 PCIe x 16 wired as x8
  • 1 PCIe x 16 wired as x4
  • 1 PCIe x 16 wired as x1
  • 1 PCI 32/33
Slot configuration for Core i7X CPUs
  • 1x PCIe x16
  • 1x PCIe x8
  • 1x PCIe x4
  • 1x PCIe x1
  • Slot 1 is not active in this configuration.


As you can see, it depends on which cpu you have... there are two 16x slots if having a Xeon or i9 , and the 2nd 16x slot would allow to see all 4 drives. But in case of an i7 cpu, as you can see, things are quite different.
So, if you have a xeon/i9 , just change slot to the 2nd 16x wired one. If, instead, you have an i7 (as I suspect), you are limited to see 2 m.2 using the 8x slot ( and you could add a 3rd in the 4x slot, using some cheap adapter )

Happy owner of a dual silver T7820
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