Built a new PC yesterday, all new parts except the GTX 1080 I brought from my old system until I find a replacement.

Noticed a strange interaction with my monitor setup that I need help pinning down.

Side note, please be aware this is in a Hyte case, so the GPU is in a riser, this may be a cause, but I haven't tested it yet.

Here is what happens, my GPU has 3 DP connections, 1 HDMI, my mobo has 1 of each.

The system will not boot under these conditions:

DP in any GPU port alone.

DP in any GPU port and HDMI in GPU slot.

I know it's not booting as my light controller doesn't kick in to change the lights. I wish my board had an LED readout for error codes.

The system will boot under these conditions:

HDMI alone on GPU.

HDMI alone on motherboard.

DP alone on motherboard.

DP alone on motherboard, HDMI on GPU.

DP on GPU, HDMI on motherboard.

Additional details, display port is going to my primary 1440p display, so needs to be on the GPU. HDMI is going to a secondary 720p TV. Doesn't need to be on gpu, but would like to figure this out in case I upgrade the display before a new GPU.

Once I am booted and in windows, I can move my cables to any port, including HDMI back to the GPU.

My suspicion is there's some sort of detection on the GPU that's faulty? There is another 1080 in a PC I can borrow, but not for a few hours.

Specs, 13700k, Asus Z790-p prime motherboard. I have not updated the Bios for this, I just got the board. Might be worth looking into. 32gb ddr5 team group ram. I am on Windows 11.

Any ideas or suggestions for what to look for in bios or in windows?

Update: bios is 0806, newer version 0809 is available but says it's memory compatibility. Avoiding that for now.