Top causes for wakeups: 18,2% ( 89,3) knotify4 : schedule_timeout (process_timeout) 12,4% ( 60,8) <interrupt> : uhci_hcd:usb3, yenta, nvidia 11,5% ( 56,4) <interrupt> : PS/2 keyboard/mouse/touchpad 10,8% ( 52,9) plasma : schedule_timeout (process_timeout) NB: Actually this is using KDE 4.0.3 packages but I could only select 4.0.2 while bugreporting