ATI Radeon HD 5770 resolution issues I have a new MacPro5,1 running 10.6 with the ATI Radeon HD 5770 graphics card... Today I was using it and the resolution just shrunk to 1680x1050 and thats as high as it will go.  I also get "formatBus" errors when running several programs? (Shake,Etc)

Any idea whats going on?
Have you tried resetting the PRAM?
Also run the Apple Hardware Test to see if it comes up with any GPU errors.