Well I tested today with HDMI and it works now. I'm guessing it's the motherboard's Uefi(bios) Displayport implementation/handshake. The HDMI in my monitor only supports up to 120hz instead of 144hz using Displayport. @samesame , try with a HDMI cable and turn off both monitor and pc and turn everything back on and see if you can get csm disabled working.
I found a link from nvidia's forums with a user having similar issue and the user had a Gigabyte AM4 motherboard but I'm not sure if that user was able to fix it.
I'm not sure how widespread is this issue and if other users have noticed this issue.
Hopefully you can help us with this issue?
I am having VERY similar issues. At first I couldn't get the board to boot with HDMI, so I tried DVI. That worked. Then I left the DVI cable plugged into the video card and plugged in the HDMI cable as well and after a few powercycles it booted into HDMI. I did the same thing with DisplayPort and HDMI - left the HDMI cable plugged in with the DisplayPort and eventually it booted with DisplayPort.
I'm still having issues booting after turning off the power supply, or after a long shutdown period. I push the power button, no display, the board doesn't seem to POST. I push the power button again to turn it off. Then push the button again and it boots. My CMOS settings stay, everything seems fine.
UPDATE: Just tested with both CSM turned on and CSM turned off. No difference for me, I am able to boot either way. Will test cold boot now. Here is my GPU info:
UPDATE2 COLD BOOT: I have no issues with stuff not getting saved in BIOS, and once I've booted once on DisplayPort, I don't have to go through the whole plugging in various video formats thing. BIOS displays using DisplayPort once it's been booted into it once. I'm sure if i have to reset CMOS, I'd have to do the whole chain of DVI->HDMI->DisplayPort again. CSM settings don't seem to matter for me, but I still have to double-boot the computer to get it to boot after Cold Boot. I push power once, fans spins up, lights turn on, then nothing. Push power again, it immediately powers down. Push power a third time, boots into windows (or BIOS, with all settings saved) on DisplayPort with no issues.
27.3 KB Views: 58