GTX670 Big Sur - 3 monitors

[ade25]

Hi all, I have a build running Big Sur and currently using my trusty GTX670 4GB card. I know I can't go any higher OS wise now but I'm happy with BS currently. My problem is this. I have to unplug my dvi-i and display port, leaving my dvi-d plugged in untill i get to opencore loader, then i can plug the other 2 back in during boot! Do i need to do something here post? I'm very new to this. If I leave them all in, just a blank screen.

My processor is a core i5 10400F so no iGPU

Hope this is sufficient info for someone to help. I am totally new to open core so would need more specific info to change this. sorry, and thanks