[alx_chem]

Well, I've tracked down the culprit to an if clause in my compiz-manager script, that invoked compiz with the --loose-bindings flag. I commented that out, and all my refresh problems were gone. The only thing that still troubles me is that even though I tried some 3D games at high resolutions without a glitch, glxgears can't go over 60fps and the gears' revolution is quite jumpy.