I have this weird issue that's happened since swapping out a 2080Ti to a 3090. My PC is connected to a Samsung Q95T, which, when I boot up won't see the PC. You can tell the PC has gone to Windows start though - just not putting out anything on HDMI. However, if I switch the PSU off and on and then reboot, it picks up the card fine. It also works fine when just restarting the PC.
What is different from a boot where the power was completely off to one where the PC is off but PSU is on?
What is different from a boot where the power was completely off to one where the PC is off but PSU is on?