ASUS TUF 4090 runs at x8 and sometimes x16 at random startup - x670e Hero motherboard

[COCOLELE]

Hello,

For some unexplained reason my TUF 4090 card only runs PCIE4 x8 in 9 out of 10 startups, and 1 out of 10 startups the card runs at PCIE4 x16. When the card boots in x16 speed it will remain that speed throughout the session until i reboot. After reboot, it most probably goes back to x8 speed. The card should always start in x16 speed, but it doesn't.

To clarify, the x8 does not change to x16 when putting the card under heavy load (benchmarks) or playing intensive games. The x8, or x16, will remain that speed throughout the session, until i reboot.

I have tried to find possible explanation to this but i can't. (e.g. if something is stealing PCI lane speed etc)

I have a prebuilt PC with below specs. I have tried every possible solution to the problem, updating bios on motherboard, updating vbios, played around with mobo bios settings like forcing x16 speed, disabling integrated gpu etc.

My motherboard should not share the PCI16_1 slot speed with anything if PCI16_2 slot is empty (which it is).

I have also tried to reinstall windows 11 four times, the problem persist exactly like above even before installing any drivers. And i have run the card in Eco mode and Performance mode, no difference in this behaviour.

Question:
As this is pre-built PC, should I send it back to the builder for review? Or is this a driver/bios problem (since i sometimes run the card at x16).

Thing is I have already sent the PC back once before (few weeks ago), where my previous problem was motherboard not detecting my vcard. For that problem they concluded that my motherboard was faulty, now i dont have this problem as they exchanged to a new x670e Hero motherboard. But this x8 problem persists, but not always!

When i emailed them that the x8 is not fixed they claim it ran x16 during their tests (which i do not blame, as i sometimes get x16 speed on bootup).

Any suggestion on what i should do?


My specs:
Mobo: ASUS x670e Hero (bios 0805, tried 0705 before that)
GPU: ASUS TUF 4090 24 gb (non-oc) - latest v.2.1. vbios. (had the v2 bios before)
CPU: AMD 7900x (stock)
RAM: Kingston Fury Beast RGB 5600 2x16gb
PSU: Corsair RM1000e 1000w
SSD: Kingston FURY Renegade PCIe M.2 NVME SSD 2TB. PCIe4
OS: Windows 11, latest version

[STARRAIN@ROG]

Hi COCOLELE,
Not sure if you had mentioned the x8 issue when you send it back to the builder previously.
We would suggest send it back to the builder and describe the x8 issue and occurrence frequency in detail.
If they cannot find the solution for you, please send your motherboard and graphics card to our RMA for further examination. Please also describe your issue and occurrence frequency in detail when send RMA.
Thank you.

[COCOLELE]

Hi COCOLELE,
Not sure if you had mentioned the x8 issue when you send it back to the builder previously.
We would suggest send it back to the builder and describe the x8 issue and occurrence frequency in detail.
If they cannot find the solution for you, please send your motherboard and graphics card to our RMA for further examination. Please also describe your issue and occurrence frequency in detail when send RMA.
Thank you.

Hi,

Thank you for the reply, indeed i described the x8 issue the first time i sent it back. They stated that it ran x16 when they did their tests on the new mobo.

This makes me think if there is any issues with the bios or Asus vbios for their 4090 cards, hence the reason for posting this.

One person in a Reddit forum with x8 problem on asus motherboard stated that he received a reply by ASUS that a bios for the motherboard will be released in Q4 to solve this (indicating that it is the motherboard bios at fault).

Do you know if there is such issue with latest gen Asus hardware that limits the 4090 performance? If there is then perhaps i should wait for the update?

Or can it be some drivers that are at fault here?

If not, i will probably send it back again for review.

[STARRAIN@ROG]

Hi COCOLELE,
May I have the link of the Reddit forum discussion you mentioned?
Is it also ROG CROSSHAIR X670E HERO motherboard?
Thank you.

[Murph_9000]

Games, even heavy ones, are not going to be particularly good at stressing the bus bandwidth to test for some type of power saving via bus reduction. GPU-Z has a tool which claims to provide the correct stress on the bus. It's the "?" beside the "Bus Interface" on the "Graphics Card" tab.

[COCOLELE]

Hi COCOLELE,
May I have the link of the Reddit forum discussion you mentioned?
Is it also ROG CROSSHAIR X670E HERO motherboard?
Thank you.

Yes, it is still the x670e Hero motherboard, a new one that replaced the old one that was troublesome.

Here is the main Reddit link: https://www.reddit.com/r/nvidia/comm...s_motherboard/

But there are other reddit threads where people state they are stuck in x8 on asus 4090 cards, this youtuber for instance:
https://www.youtube.com/watch?v=LwpdtdeAVpk&t=1s


As for the GPU-Z stress test, yeah i tried it, it does not change x8 to x16 when the card booted in x8. People seem to confuse x8 and the "Gen of PCIe" under load and how it is idle.

It changes from x8 Gen 1.1 to x8 Gen 4.0 when under load, same thing with x16 @ 1.1 to x16 @ 4.0. My card remains at x8 level, or x16 level, depending on successful boot or not.

[STARRAIN@ROG]

Hi COCOLELE,
Sorry I don't find the discussion about "the motherboard will be released in Q4 to solve this" in the links you provided.
Not sure if it is my missing. Would you mind to tell me the discussion on which floor or the time point in the video?
Thank you.