I decided to try and upgrade my old 2009 Mac Pro and update it based on the various guides that I've seen online. I figured the best 1st step would be to make sure that I flash it from 4.1 to 5.1, and if that works, I can purchase the rest of the hardware and do the upgrade.
The first time I tried doing this, it didn't work and supposedly it was due to me having a non-Apple graphics card. So I went and bought an ATI Radeon HD 4870. After installing it on the computer, it won't boot properly and when the main screen loads, it's all scrambled.
However, if I boot into recovery or safe mode- It'll work fine and the screen will be normal. Any Ideas?