...
we need more infos
new gpu in new mobo?
wrong pci-e slot?
wrong pci-e slot as graphic slot used in bios?
did you flash a vbios
did you bought card used
what does the mobo say (beeps with motherboard speaker) or show via debug led?
we need WAY more info
PC: R7 2700X @PBO + RX 580 4G (1500MHz/2000MHz CL16) + 32G DDR4-3200CL14 + 144hz 1ms FS P + 75hz 1ms FS
Laptop: R5 2500U @30W + RX 560X (1400MHz/1500MHz) + 16G DDR4-2400CL16 + 120Hz 3ms FS