tmmy34
Hi. I have 12900K stock

32 GB 2x16 GB DDR4 3600mhz

Palit Gamerock Pro OC rtx 4090

1300W Seasonic Platinum Prime

Windows 11 2H22. Updated new nvidia drivers.

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?

Tested 3dmark and its fine.

I generally suggest if people are changing out graphics cards for them to clean their drivers with Display Driver Uninstaller (which has an option inside it to clean the driver and shut down the system EXACTLY for when you switch cards) beforehand.
It's hard to tell what the light was about without more information, but could have been the driver or the motherboard having some other oddity recognizing the new 4090.
In any case since you have already done the switch and it seems to work now, what i would do is just do a DDU cleaning and install your driver again. This will make sure that atleast driver wise you have an absolute clean slate for the 4090, and if there is any further complications it's not software/driver.
 
You can find DDU here: https://www.guru3d.com/files-details/display-driver-uninstaller-download.html (the page will tell you, but if you wouldn't read it for some reason it's HIGHLY advised that you run it only from Windows Safe Mode)

ty_ger07
I would suspect fast boot optimizations caused issues initializing right away, and that is why it seemed a bit odd at first.
If you had stuck it in a fresh new build which hadn't already learned other hardware, it would probably have behaved more normally.
I would not worry.

This could be the case absolutely, Fast Boot/Safe Boot, turn these off in the BIOS (i would still do the clean drivers however).