6900XT reporting PCIE x 8 4.0 in GPUZ

I just noticed that my 6900XT is only using 8 lanes on the x16 slot. Not sure how long its been like this. I know it shouldn’t have a noticeable affect on performance, I’m just wondering why it is doing that. It is not my intention to limit it to 8 lanes.

I have Gigabyte X570 Aorus Ultra, 5900X, SN850 PCIE Gen 4.0 NVME m.2, 2x SATA SSDs, 4x 8GB DDR4.

6900XT is in the first slot of the board, highest/closest to the CPU.
Gen 4.0 NVME is in the first slot of the board, highest/closest to the CPU.

I don’t think that just a single 4.0 NVME drive limits your x16 slot on X570 platform.


Try clicking on the question mark besides the bus interface and start the render

Other than that is there any other PCI-e cards or m.2 ssds or wifi cards installed

What are the bios options for bifurcation set to

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I think both the top two slots can be adjusted for bifurcation, see if you have this enabled as described above and see if the BIOS is only allocating 8 PCIe lanes to the top slot.

This is normal basically when the gpu sits at idle.
Run a gpu benchmark like valley or a game or whatever.
Then the gpu should jump to 16x.

power saving thingy. :slight_smile:

In Bios the x16 is set to “Auto” I think the other options were like 2x8 or 4x4 and something else.

I ran Timespy at 2690MHz and 390W and refreshing GPUZ still showed x8 4.0. :man_shrugging:

Any junk in the slot? Or on the cards pins?
Tried a different slot or Mobo?

Check the motherboard specifications for PCIe lanes:

  • If top slot is occupied and second is not, all 16 lanes are active on top slot.
  • If second slot is occupied, x8 to top, x8 to second
  • Third is always x4
  • The first m.2 is always x4
  • Second m.2 share two lanes with third m.2 for x4/x0 or x2/x2

Make sure your card is in the proper slot then report back. The good news is that you are losing like 1 FPS, tops, in a x8 4.0 card, so no real loss other than satisfying your OCD.

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