@Pedrobas: I checked my CCC and sadly I do not have the same options as you have in my CCC. I think it's because I have different card then you have. I beginning to give up.
When I uninstall MMM p2 my lag and crashing disappears but the mouse issue is still there. When I uninstall MMM p3 my mouse issue disappears. I don't know whats wrong with my rig, but I don't want to play the game without MMM part2 and part3...
If there are some people here with a HD6990 card and different CCC settings then the default maybe you can post your CCC settings. I tried everything I could think of to sort out this problem but I don't have any ideas left now.