Wow, so rendering glxgears directly (bypassing Compiz/Unity) is still slow? That's weird. You know it only works for fullscreen windows, right?
Sounds like compiz/unity in the background is still hammering your GPU when it should not be.
Please try plain compiz so we can rule Unity in or out. To do that you can untick the Unity plugin in CCSM, or just install
gnome-session-fallback and log in to Gnome Classic (Compiz without Unity).
Wow, so rendering glxgears directly (bypassing Compiz/Unity) is still slow? That's weird. You know it only works for fullscreen windows, right?
Sounds like compiz/unity in the background is still hammering your GPU when it should not be.
Please try plain compiz so we can rule Unity in or out. To do that you can untick the Unity plugin in CCSM, or just install fallback and log in to Gnome Classic (Compiz without Unity).
gnome-session-