Hello, In struggle to use OS X Yosemite (and, hopefully, El Capitan) on my Mac Pro 1.1 I came across this thread - however, I have a few follow-up questions. 1. Do I need to buy an Apple branded ATI Radeon HD 5770? Or can I use an ordinary, non-Apple video card? 2. It says something about properly mac-flashed video cards - what's the process of flashing a video card? I tried to use a newer, stock video card (I believe it was from ATI Radeon HD 9800 Series), but the screen remained black for days.