I have a multimonitor setup using a single Asus hd 6950 2gb.When I play games in fullscreen, they run smoothly. When I try to play in windowed mode/borderless , I get horrible microstuttering.
The fps will remain high and stable, but look horrible and laggy. I've tried changing just about every setting in ccc and nothing makes it any better. Vsync on or off makes no difference. Disabling aero has no effect either.
The problem, I believe, is that the core clock constantly jumps between 450 and 810 when not in fullscreen. Gpu-z seems to show it jumping down at the worst times during the stutter.
I have also noticed this in browsers and youtube videos.