KDE becomes non-responsive. OpenSuSE 13.1 64B

KDE becomes episodically non-responsive. A typical example is having Kontact running, the browser, and a couple of LibreOffice documents open. Things will be running smoothly, then KDE stops responding to the Keyboard, mouse click and mouse hover. The timing of this appears to be random, although it can't go more than a few hours without this happening.

Any ideas would be helpful.

Thanks.