"crasy" daemon ksoftirqd (SuSE 9.2 AMD64, KDE 3.3 or 3.4)

Hello Why, after a long time of use, does this daemon ksoftirqd become "crasy" by using more than 95% of the CPU ? I got this under SuSE 9.1 AMD64 with KDE 3.2 or 3.3. I get it again under SuSE 9.2 AMD64 with KDE 3.3 and now 3.4. Kind regards Pascal