Version: (using KDE 4.2.98) Installed from: SuSE RPMs i have installed the latest stable nvidia-driver 185*. and everytime i change the resolution when the desktop-effectsare activated the system crashes. monitor goes black and changing to any terminal isn't possible. if i change the resoulution wihout desktop effects all works fine.
kwin also crahes when openeing gimp with desktop affects. this doent't happen with other compositing managers/window managers. but it could be a driver problem.
as you mixed two issues: the first sounds like a driver problem. If X crashes it's not kwin's fault. the second sounds like a kwin crah: please report the crash with the help of DrKonqui.