Hi, I just purchased an RX 480 gpu and on first boot nothing is displaying on my monitor, I tried my old GPU to see if it was the motherboard but it worked find besides defaulting to some internal graphics instead of the graphics card. The old graphics card was the Radeon 7700 series. The computer was a prebuilt Dell Studio XPS 8500 if I recall correctly.
PSU: Corsair CX550M
Windows 10 Pro 64-bit
Intel Core i7 3770 @ 3.40GHz
Ivy Bridge 22nm Technology
8.00GB Dual-Channel DDR3 @ 798MHz
Dell Inc. 0YJPT1
Sorry if I'm missing anything I'm not used to having tech problems.