I have the exactly same build! B660-i, 12600K and 7900 XTX reference...but i use a nr200p max. I had lot of driver timeout and the cause was XMP Profile. Just increased DRAM voltage a little and solved it.
Think the video card issue may be the 90 degree riser card that is included with the Fractal Ridge, been a lot of talk on various forums about it. Posts are stating that folks are having issues with the 90 degree riser card not running PCIe 4.0, and that it will run at PCIe 3.0 speeds even if they set it manually in BIOS to PCIe 4.0. Other posts stated sometimes it would work at PCIe 3.0, and sometimes it would not work at all.
I just got this case. The problem is with the smaller riser card (not the 90 degree riser card), a replacement needs to be sorted/issued by Fractal. For the time being use gen 3 mode in the BIOS.
Saw a photo of the smaller (straight) riser card in a forum post by someone experiencing the issue. In the photo, it appears that there may have been an issue with the solder printing on the PCB (i.e. SMT screen printing). The solder appears to be smeared on the PCB of the smaller riser.
