Strange GPU POST/reboot issue [Resolved]

[Anonymous_0172]

Hi, I'm having a tricky issue with my PC at the moment. It is suddenly failing to POST most of the time (~8 times in 10), with the VGA Q-LED remaining lit. If I keep trying, eventually it will succeed and boot Windows 11 with normal display output, but within a few seconds the monitors will go black and the system reboots back to a failed POST state. Weirdly, sometimes when it does boot Windows, it will boot with only a single monitor, and with the device "stopped (code 43)" in Device Manager:
https://i.~ibb.co~/R69L3QT/Screenshot-20230117-131026.png https://i.~ibb.co~/yYy3YNW/Screenshot-20230117-133521.png
In this state, display output is fine on the single monitor and the system seems stable, with an uptime of several hours rather than seconds and can browse/watch vids etc. If I install the Nvidia drivers, the other monitors start displaying an output, but the system instantly experiences a few lag instances before the displays go black and once again the PC reboots back to a failed VGA POST state.

Other info:
- No flickering/artifacts
- Both BIOS and HWInfo report +12v values between 12.172v - 12.268v
- GPU is now reported running at PCI-E x16 @ 1.1
- Will happily sit in BIOS/as above/Windows safe mode without any issue
- All temps fine
- No spare PSU/GPU to swap in and test
- Overclock settings removed
- GPU, RAM, power cables checked and reseated

Motherboard: Asus ROG strix x570-f
GPU: Asus TUF RTX 3070
PSU: Superflower leadex platinum 1000w

I wouldn't have expected a GPU to fail in this way? Any thoughts on this one appreciated, thanks!

 

[Tetras]

Have you tried changing the PCI-E setting in BIOS to 3.0 or 2.0?

Have you ever had any issues with the case and alignment of PCI-E cards?

Case is clean (i.e. not super dusty)?

What's warranty status on the card?

 

[Anonymous_0172]

Have you tried changing the PCI-E setting in BIOS to 3.0 or 2.0?

Have you ever had any issues with the case and alignment of PCI-E cards?

Case is clean (i.e. not super dusty)?

What's warranty status on the card?

Setting the PCI-E slot from auto to gen3 in BIOS is something I completely forgot about, but so far seems to have resolved it. Cheers, you've saved me a lot of hassle!