Put M2 in slot 3-4 or 5 , dont' use slot 1-2 if no want with a 4090 pcie go 4.0 8x and bottleneck the video card, for pcie work 5.0 mode need all connected parts be pcie 5.0 and neither your gpu or M2 are 5.0 so gpu one will go down to 4.0 8x, it's e...
yes must use the top slot pcie always for gpu on all z790 boards, also usign bottom one if no have an insane huge case , really hard it can fit or get good cooling
If no have already bios 0816 , try put m2 in a slot 3-4-5 and bios update so you get alsoget board reset https://dlcdnets.asus.com/pub/ASUS/mb/BIOS/ROG-STRIX-Z790-E-GAMING-WIFI-ASUS-0816.zip?model=ROG%20STRIX%20Z790-E%20GAMING%20WIFI
