Question PC not booting when graphics card is connected with DisplayPort ?

[weatherdude]

GPU: Sapphire Pulse AMD Radeon RX 6500 XT
CPU: AMD Ryzen 5 5600G
Motherboard: Gigabyte B550M Aorus Pro
RAM: G.Skill F4-3600C18D-16GVK 16GB (2x8GB)
PSU: Seasonic S12III-500 (500 watts)
Monitor: AOC G2460V
OS: Windows 10 64-bit

Earlier in March 2022 I built a mostly new PC with a CPU, Motherboard, and RAM. I went with the bare minimum to start off with. Later on I added a new SSD and everything was great. In September I decided to get off of the integrated graphics and bought a new Radeon RX 6500 XT. My problem started there.

Specifically, when the DisplayPort cable is connected to the graphics card (and monitor) then my PC doesn't boot up. The case fans spin and that's it. I can't even shut off the computer with the power button and instead have to flip the switch on the PSU. When I unplug the cable and turn on my PC I can then hear the GPU fan spin up.

I found a workaround by plugging in the DP cable after the boot up process begins. The boot up proceeds normally and everything works fine. It's odd and inconvenient but I had no stability issues or graphics corruption or anything. I could even restart my PC without disconnecting the cable. Shut down and Sleep still needed it unplugged to start again though.

Well it was fine until today when the monitor lost the display signal while I was on the Windows desktop. Plugging in the DP cable after my PC boots no longer outputs any picture. So I tried using HDMI instead and got into Windows but it was running the basic Microsoft display driver. I had to reinstall the AMD drivers (22.11.2) so something happened there I guess. Right now my PC seems to be running fine and I don't even have to unplug the HDMI cable to start up my PC. FreeSync doesn't work anymore though because it needs DisplayPort?

I'm thinking the graphics card is the issue since my monitor (and DP cable) was working with the integrated graphics and my old computer. Anything I'm missing? Any help is appreciated!

 

[ak47jar3d]

FreeSync should work via HDMI..... I would just do that. You likely have a bad dp port......

 

[weatherdude]

I did some testing after I found my old Radeon RX 560 and a laptop and here were the overall results:

iGPU
DisplayPort: OK
HDMI: OK

RX 6500 XT
DisplayPort: Bad
HDMI: OK

RX 560
DisplayPort: Bad
HDMI: OK

Laptop
DisplayPort: OK


Having the same problem on separate video cards likely means they aren't the source of the problem. DP working without issues on the integrated graphics and a separate laptop also probably excludes my monitor. I wish I had another monitor with DisplayPort so I could rule it out. Oh, also the DP starting working again the way it did before on my GPU after I did all the testing. No idea why.

I'm back where I started but I now think it could be a motherboard problem or something. My PC not starting only when DP is connected and only on discrete GPU's is very strange. As for the FreeSync I think my monitor only supports it via DisplayPort. I couldn't toggle it on or raise the refresh rate to it's 75 Hz rating when on HDMI.