Mac Pro 3,1 Black screen when booting into windows

[Mac64ps]

Hello, I am currently running an early 2008 3,1 Mac Pro running 10.11.6 and had successfully installed and ran windows 8 and 10 on separate drives while using a ATI Radeon 4870 HD 512MB. Mac OS as well as windows 10 worked perfectly on it.I swapped my graphics card to a ATI Radeon 5870 HD 1GB and the computer is able to boot into Mac OS just fine. However, it is unable to boot into the dedicated windows 10 drive that I was using prior to swapping the GPUs. When I try to boot from that drive I am presented with a dimly lit black screen and after a few minutes the fan speed with increase a bit. I tried to make a fresh install of windows 10 on another unused drive in the computer however when trying to boot from the windows 10 installation dvd-r I’m prompted with the same dimly lit black screen. Does anyone know what might be going on here or how to fix it? If more specs or details are required I’ll be happy to provide them as soon as I can.