I've have 2007 Mac Pro 1,1 for which i bought a Sapphire Radeon HD 6850 to use with some light FCPX editing and few games. I know that PC Radeon card won't get me boot screens and rarely be recognized correctly, but i couldn't find anywhere is flashing important for sheer functionality of the card? When i bought it I've tested it for few hours in Borderlands 2 and Arkham City just because i know that if GPU has problems they will show up in games. All went ok with maxed or nearly maxed out settings on 1080p. It showed no bugs, screen flashes or graphical glitches. Then i tried to run some Benchmarks and ran into a few problems. Luxmark and Cinebench seemed fine And so did the Unigine Valley Though I'm not sure if the results are OK? But i ran into a problem with GFXbench GL and CompuBench CL. The first didn't want to run (nothing was supported) and later one just loaded bench screens (YT video) Also, yesterday i had a problem with ugly pixelation in OS X 10.10.5 and red, green and yellow pixels on blacks parts of the videos (Quicktime, VLC, FCPX). It sorted itself after reboot. So are these bugs related to non flashed card and will they go away after the flashing or is flashing done only for boot screen purposes? Ive read here that HD7950 can have some glitches if stock PC card is used, but i cannot find info on these bugs I'm having troubles with. Thanks in advance for any info on this! Ljuba P.S. I aslo have 1080p Youtube playback stops and (few seconds) freezes, just like i had with my Hackintosh (with GeForce GT220) but I've never experienced these problems with stock GT 7300. Edit: I just wanted to add, if it is related in any way, that I'm using molex adapter from DVD at the moment to power my card. Still waiting for mini 6pin adapter to arrive.