graphical corruptions in kde4/qt-apps
for those of you experiencing the graphical corruptions/lags with qt4-apps or kde4-apps,
enable both options concerning "Sync to VBlank", this should solve the coarsest ...
X Screen 0 > X Server XVideo Settings > [x] Sync to VBlank
X Screen 0 > OpenGL Settings > [X] Sync to VBlank
the advantage is that for this you don't need to enable this setting in the compiz-fusion settings (ccsm) or kde4 system-settings
hope this helps some of you