Question RX6600 - Displayport only works in BIOS and safe mode

[ILUMEG]

This issue has me stumped. I have an RX6600 GPU that I connect to my monitor via a displayport cable. Everything works fine right until the point where I install the AMD drivers for this GPU, where it just completely loses signal. It still shows me de BIOS screen and I can access and stay in BIOS without losing signal perfectly fine. If I reboot windows in safe mode, it also works normally. It's only when the drivers load that it loses signal.

If I connect the monitor via an HDMI cable instead, it also works fine. This issue happens with all three displayport ports (?) on the GPU.
Bizarrely, a displayport to HDMI cable also seems to work, although it limits my refresh rate so it isn't ideal. I would think that if the displayport ports weren't sending signal this wouldn't work.

Full specs:
-OS: Windows 11
-CPU: Ryzen 5 3600
-GPU: RX6600
-RAM: 16GB DDR4
-Motherboard: Gigabyte B450M S2H
-PSU: Nox Urano VX 750w

Troubleshooting done:
-Uninstalling drivers with DDU and reinstalling. Has been done with multiple driver versions, including the oldest I could find for this GPU.
-Testing in a different OS: Tried in a clean installation of Windows 10.
-Updating BIOS
-Clearing CMOS
-Changing some BIOS options like fastboot and csm
-Tested with several monitors and displayport cables

Troubleshooting I cannot do:
-Testing on a completely different machine. I don't have another system I can install this GPU in, sadly.

The fact that it doesn't happen without the AMD drivers loading is pushing me away from this being a hardware issue and into a software one. What do you guys think? Any ideas? Anyone with the same problem?

 

[Lutfij]

Welcome to the forums, newcomer!

Motherboard: Gigabyte B450M S2H
+
Updating BIOS
What BIOS version are you on for your motherboard? Disable CSM, if it's enabled thought hat might prevent you from booting into the OS.

Uninstalling drivers with DDU and reinstalling. Has been done with multiple driver versions, including the oldest I could find for this GPU.
When using DDU, remove all GPU drivers(Intel, AMD and Nvidia) from your platform. Manually reinstall with the latest GPU driver sourced from Nvidia's support site in an elevated command, i.e, Right click installer>Run as Administrator.

 

[ILUMEG]

Welcome to the forums, newcomer!

Hi! Thank you for you suggestions.

What BIOS version are you on for your motherboard? Disable CSM, if it's enabled thought hat might prevent you from booting into the OS.

I'm on version F64f. I had CSM already disabled, sadly it made no difference.

When using DDU, remove all GPU drivers(Intel, AMD and Nvidia) from your platform. Manually reinstall with the latest GPU driver sourced from Nvidia's support site in an elevated command, i.e, Right click installer>Run as Administrator.

It didn't work either. I assume you meant the latest AMD driver.