Well i m having a wired problem , i just got myself a new gigabyte rx480 g1 for my 2010 mac pro as i m running 2 monitors , 3440x1440 & 2560x1600 .. and 5770 was not powerful enough to handle that much pixels .. anyways back to the problem .. before rx480 i got myself gigabyte r9-280x and i was working totally fine with internal power supply , my friend bought from me for few days and eventually burnt the card .. and i had to get myself a new card and with the help to this this awesome forum i got myself rx480 g1 .. i live in a third world country where multiple brands are not an option .. the only option i got was this 480 g1 .. anyways i got the card & i did followed the guide like this Rebooted the machine into recovery with 5770 Gpu & run the command Rebooted again into OS . . . edited the AMDRadeonX4100.kext and the ran kextwizard ... shutdown the computer & removed the 5770 & plugged the rx480 and turn on the machine ... even thou i was able to see the RGB and Fans spinning of the card & waited for like 5 to 10 min and i had no display tried again and still no display plugged the rx480 in to windows gaming machine and i got the display and everything was working fine . i then again plugged in the card to the mac and still no display .. then i used my 980ti hybrid from my windows machine just to make sure that things are working .. but again i was not able to see any display with that card too .. anyways i plugged back the 5770 and things again start to work perfectly fine .. soo what i m doing wrong ? ? ? ?