Recently I installed Arch linux and Kde for the WM.
I am currently using "KDE Platform Version 4.5.1 (KDE 4.5.1)"
The desktop effects "composting" works but everytime I make a small change to any of the settings the screen freezes for an idefinite amount of time! and when this happens I have to do ctrl+alt+F1 and go to the command line and kill X and then re-enable composting !
Can anyone tell me why this is happening? what should I do to rectify this?

I am having an Intel onboard G41 chipset.
I installed "xf86-video-intel" driver.
Edit: I changed the xf86-video-intel to xf86-video-intel-newest from AUR

Known issue with KDE 4.5. Not one of KDE's better releases, IMO.

Adam