Question No Displayport signal on boot-up after HDMI swap works perfectly ?

Nov 18, 2022

I have seen problems with display port cable around but nothing has worked for me so far and none of the existing threads quite fit into my problem.
So, last week I finally finished my new rig by buying a new GPU. I was just waiting for the prices to go down. I bought Nvidia GeForce RTX 3060Ti. Before swapping the GPUs my setup was as follows:

MB: Gigabyte B550M AORUS ELITE
CPU: AMD Ryzen 7 5800X
GPU: Sapphire Radeon RX 580 NITRO+
Monitor: AOC Q3279WG5B

Everything was working properly. In my original setup I did not even have HDMI cable, only DP. However, after I swapped the GPUs and press the power button for the first time, there was nothing. Just black screen after which the message No DP signal appeared. I could tell nevertheless that the GPU was working. Therefore, my initial reaction was that it is the drivers issue. I swapped Geforce for Radeon so my first instinct was to try it with HDMI cable which worked. After uninstalling Radeon drivers and installing Nvidia drivers I restarted my PC and everything was working. However, the next day I would get the same issue. I would turn on the computer and end up with No DP signal message on the monitor. I would then have to turn off the PC, unplug DP cable, plug in HDMI cable, turn on the PC after which I would unplug HDMI cable and plug in DP cable and everything would work perfectly again.

So to summarize. After installing new Nvidia GeForce RTX 3060Ti and installing Nvidia drivers my DP cable does not send signal into the monitor upon boot-up, however, it works completely fine afterwards. The monitor will boot up only with HDMI cable. What should I do?

Thanks for reading all of this.

Nov 30, 2022
I am having very similar issues, will boot with display port cables disconnected, but not otherwise.
Found that if I enable CSM (compatibility support module) in the BIOS I can boot normally with display port cables attached. (This can however affect other things, so please be aware before you do it).
Just found this - Here , I am going to try it tonight and see if it works, I realise this is for an Nvidia GPU, but there maybe something similar for AMD GPU's.
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