OpenSuSE11 - ATi proprietary driver - refresh rate won't stick
I am using OpenSuSE11 and installed the ATi proprietary driver via the OpenSuSE repositories. I now have to control my graphics card settings via the ATi Catalyst Control Centre, as opposed to YaST. It reports my monitor as having a max refresh rate of 60Hz, yet keeps setting its actual refresh rate to 75Hz. 75Hz looks OK until I try to view anything with mid-shades of grey, like this forum - then the screen flickers and jumps all over the place. I can manually set the refresh rate back to 60Hz which works fine, but then every time I reboot it reverts back to 75Hz.
Is there a file I can edit manually to stop this?
Any help much appreciated.