My configuration is as follows:
Gigabyte Z390 Aorus
Gold 1000W PSU
Acer XV273K 4K 120 Hz HDR 400 Monitor
Gigabyte Reference RX480
Alternatively - ASUS Strix Vega 64
I am consistently seeing an issue on first boot, no matter which graphics card I use -
When Windows loads it is capped to 1024 x 768 resolution, the graphics card and monitor are detected, 3D works as normal, all graphics sensors are able to be polled.
I can fix the problem one of two ways:
Plug the display port cable in to a different port on monitor and graphics card
At first I was wondering whether my card wasn't receiving power until too late and missing UEFI boot or something, but the fact that it is all detected properly and works fine after changing ports indicates this isn't the case.
The only other idea that I have is that the monitor, being a 4K 120 Hz displayport 1.4 panel, is quite extreme.. could the older cards be struggling with it?
Ideas on a postcard.