Sonicsam925

Specs: Asus prime z370-a Intel i7-8700 Gforce gtx 1060 6gb Samsung 512gb ssd Corsair - vengeance rgb pro 16gb kit Evga - 1000W ATX /EPS 80 Plus Gold Modular Power Supply AMD rx 480 8gb Problem: In the bios it shows no gpu is plugged in when just the nvidia 1060 card is plugged in. With just the amd rx 480 card plugged in it shows up in the bios. With both the nvidia gpu (pci x16 - 1) and the amd card (pic x16 - 2) plugged in both cards are recognized and works perfectly fine and i can now install nvidia drivers. Even after the drivers are installed the system only recognizes the nvidia gpu with the amd card plugged in. I've tried 2 different gtx 1060 cards and a gtx 1080 that are all known to be working in their own system. I can run games to expectation with just the rx 480 or both the 480 and an nvidia gpu. I tried updating the bios, flashing the gpu, and made sure no drivers were installed when testing each case and then tried installing the proper drivers. I filed 3 rma requests for the motherboard only to receive the same board back over the course of 5 months and them saying nothing was wrong with the motherboard. The only thing I havent been able to test is a different cpu but idk how that could be it if both cards are recognized when plugged in together