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GPU stuck in X8 no NVME drive, no PCIE devices plugged in

tonycstech
Level 7

Z690 Maximus
i9 12900KS CPU
GPU stuck in X8 instead of X16. You can see it in the BIOS screen.
No NVME drivers.
No PCIE devices plugged in.
Used latest GPUZ to confirm the issue.

Tested PCIE lanes to the CPU with a tester, PASS
Tested GPU for PCIE lanes with a tester, PASS
Tried another GPU,  same result.
Update to latest firmware, same result.

Anymore ideas ?
Bios tweak maybe ?

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1 ACCEPTED SOLUTION

Accepted Solutions

Silent_Scone
Super Moderator

Hi @tonycstech,

I think it's fairly transparent, as per the manual. The motherboard firmware doesn’t distinguish between active devices and passive adapters when reallocating lanes; it will simply detect that the slot is in use. This will very likely be the same regardless of SKU vendor.

Silent_Scone_0-1725313874113.png

 

 

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

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44 REPLIES 44

theroc44
Level 10

I would check bios and load defaults etc see what happens. 



Nothing happens.

theroc44
Level 10

are you using GPU-z to verify? Check with CPU-z on the second page mainboard and run a test to see if its gimped at 8x.



Please read my post.

How else would I know.

theroc44
Level 10

you have nothing in the m.2 slots on the motherboard? Your using a SSD as your OS?

System specs please, thanks



pndiode
Level 12

GPU stuck in X8 no NVME drive

SA8x.jpg

SA16x.jpg

Just a suggestion! I could be wrong!

GPU Vertical/Horizontal installation: Is the computer case VGA slots and motherboard near a perfect 90-degree angle? That slight lift starts migrating towards the back of the PCIe slot and may cause X0, X2, X4 and X8. Do you have to use another instrument to remove your GPU instead of your index finger?

 

Press.jpg

GPU horizontal/Vertical installation: Is your GPU sagging? Might need a GPU lift bracket.

I could be wrong!

tonycstech
Level 7

please read my post.
Z690 Hero+ 12900KS + GPU (any GPU)
No problems with the GPU 100%.

theroc44
Level 10

Not sure why you wont just detail what specs your running CPU/GPU/HD+SSD+M.2/

Hard to determine bifurcation of CPU lanes and chipset lanes when we dont know anything other than u have any gpu installed and a 12900ks and a z690 hero.

Not sure if you have AIDA64 but if you download the one that came with the ASUS mobo, you can check exactly whats using what, for exampleaida 1.jpgaida 2.jpg



tonycstech
Level 7

CPU 12900KS i already said that>
GPU does not matter, its Nvidia. I also said i tried another GPU, same thing.
I also tested PCIE lanes with a tester, they pass. all 16 lanes work on the top slot of the motherboard.
HDD NVME does not matter because problem exists even if none of them are plugged in at all.
I can run Linux from USB and confirm the issue.
Never heard of ADA so here it is. It says EXACTLY what i've been saying.
PCIE X16 is in X8 mode.
Other devices that are currently occupying PCIE lanes are NVME (4 lanes) and capture card (4 more) so total is 16.
Without NVME and capture card, same thing .,X8  only.

tonycstech_0-1724808906207.png