opensuse 11.4 + kde + compiz = black screen

I managed to get compiz running with decoration by running it with kde4-window-decorator --replace in settings for decorations.
But there are some serious problems. If I enable kde qt event loop it just stops working, if I enable kde compatibility I can’t click on application launcher more than once. Since it does not work, I don’t use, and the main issue remains:
after some time of inactivity, screen goes black(it is actually normal), but when I move mouse to wake it I can see mouse cursor moving and nothing happens. The only way to get back to desktop is ctrl+alt+f1…5 sudo /usr/sbin/rcxdm restart . Everything unsaved will be lost.
I disabled screen dimming from kde system settings, disabled power devil, but screen dims anyway.
Is there any way to solve this?
I use compiz because in kwin all animations look rather choppy, framerate is 20-30+ fps, but still it is not fluent. It actually runs better on integrated video from intel than on my gtx 570 in this desktop pc:( If I switch engine to xRender it runs smoothly, but some effects do not work and there are another strange problems.
Thanks for any help.

after some time of inactivity, screen goes black(it is actually normal)
Yes. It will depend on the settings in Power management.
It’s a bit flaky if you ask me.

Make sure screensaver is disabled.

Forgot about screen saver, thanks:) Will see if it helps.