Hi this is my first post so please forgive me if there are any problems with it.
3-PCie slots top 2 are x16 and bottom is x2/x4. When I mount EVGA GTX 970 SC ACX 2.0 in top 2 slots I get no post and 1 long 3 short beeps but works in bottom at x2/x4. If I mount PowerColor RX 570 in top slot it works at x8, doesn't post in second slot and beeps, and works in bottom. Socket pins look OK and latest BIOS/firmware/drivers in motherboard and cards. I haven't anything in M.2 slots or other PCIe slots and RAM works in all slots. I've tried CSM and disabling secure boot. Any suggestions? RMA is not an option. Thanks.
Win 10 Pro 20H2
ASUS Prime Z390-A
I5-8400
2x4 GB RipJaws 2400 GHz XMP RAM
Corsair RM650 PSU
