I unplugged 3090 ti. And plugged Rtx 4090. And on first boot was black screen ( no signal ) on monitor, and motherboard was lightning in red. I waited 4 minutes then i heard windows 11 boot ring sound. And display appear. And its fine now. Why that happehed on first time? Just black screen no signal and red ligt in motherboard ( like before windows ). Now its fine. Should i worry?
Ever notice with newer hardware if you change your main display in windows, that display will be the one BIOS starts with? Safe mode, DDU, then install it.
OSes can set some UEFI options like time or even the startup device. Maybe the card can store and pass variables which sets the preferred output port after reboot. But I couldn’t say if this a driver-level or OS thing.
Your startup issue is a bit strange. It looks more like RAM initialization regarding the amount of time it took. I would assume that’s a one case thing becausePCIe version has been switched or if other features like rebar are in use.
JayzTwoCents did a YouTube video on this. It’s RAM training. When you change HW it kicks off to optimize itself. May take a while the first time you boot.
Watch the vid; that’s exactly what happened. Not saying this is 100% match to your issue, but does explain the black screen with successful boot. If you have an iGPU you have options.