I just bought a new graphics card to upgrade what I had for the 1st time in life. The problem is that none of my games will now run and I don't know why or how to diagnose the problem. For example, World of Warcraft says - WoW was unable to start up 3D acceleration. Steam wont even load up. Civilization 4 says: Initialized Renderer failed. Check DirectX Installation, Latest Graphics Driver and Graphics Settings.
What I had before was ATI Radeon HD 4870 512 MB (2 x 6-pin cables). What I bought and upgraded to was AMD Radeon HD 7970 Mac format graphics card (1 6-pin and 1 8-pin cables). I installed the graphics card on my own. I changed out the old cables to the new ones. It was not clear which cable goes with which on the mother board in regards to the 6 and 8-pins. I've tried both ways with no success in switching cable ports if it mattered. I'm currently running OS 10.7.5. One place poking around looking for ideas indicated that I may need to upgrade to OS 10.8.3 for graphic card drives for the 7000 series. Otherwise, I'm a total noob in the dark about this stuff and came here looking for answers. Let me know if more information is needed to help me with my problem.
Have you tried uninstalling your current drivers and updating to the latest drivers?