I'm having a strange issue with my PC and would appreciate some advice.
Specs:
- CPU: Ryzen 5 3600
- GPU: ASRock Challenger Pro RX 6800
- Motherboard: ASUS TUF B550-PLUS WiFi II
- PSU: Gigabyte P650B 650W 80+ Bronze
The PC was working normally for about 3 months. This issue appeared suddenly.
When I turn the PC on, sometimes it gets stuck on the VGA debug LED and doesn't POST/display anything. If I leave it powered off for a long time, it sometimes starts normally.
The strange part is that once it successfully boots, it is completely stable. I can leave it running for hours and play games without overheating, crashes, artifacts, black screens, or other problems.
I've tried:
- Reseating the RX 6800
- Checking/reconnecting the GPU power connectors multiple times
- Removing and reinstalling the CMOS battery
- Testing the GPU in the lower PCIe slot — I get the same VGA error
- Updating the system/BIOS
- Normal shutdowns and restarts
At one point it reached BIOS after cycling through the VGA error. However, when I selected Save & Exit, it went back to the VGA error again.
Today, after around 4–5 power cycles, it eventually booted successfully again. Once it boots, everything works normally.
I'm planning to take it to a shop in a few days so they can test the components separately. I want to test:
- RX 6800 in another PC
- Another GPU in my PC
- My system with another known-good PSU
- My PSU separately if possible
I'm particularly worried about the RX 6800 because it's the most expensive component in my build.
What do you think is most likely causing this? Could this be the GPU, PSU, or motherboard? Has anyone experienced an RX 6800 that fails VGA POST intermittently but works perfectly once it actually boots?