I am running CentOS 6 with a 780M integrated graphics using fglrx 11.7 or 11.8 with an e-machines e182HL monitor on VGA. with both drivers, after install fglrx the login screen and the gnome desktop after logging in is afflicted with horrible black flickering lines running up and down the screen. Turning on tear-free desktop fixes the problem... but it messes up full screen flash playback.
First off, it's somewhat difficult to figure out the exact video card, however I am guessing you are using a Radeon HD 3200 (780G), or Radeon 3100 (780V). These graphics cards have support for usage for the last year or two, so that should not be a problem. Anyways, I suggest changing the screen refresh rates and resolution and see if you find one that works. Also, have you tried enabling/disabling desktop effects?
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