Created attachment 103197 [details] screenshot of top When working with KDE after a while (hours) plasmashell and Xorg eat my CPU power. The system slows down. It might happen after suspend, however, I am not sure. Attached is a screenshot of top.
When I kill plasmashell and restart it again, all is normal.
Thanks, but this isn't very helpful on it's own, so I'm going to close this, but please see the linked reports. We have multiple high CPU bugs, some caused by us, some not, some fixed, some unknown. It's hard to say what the cause of each one is, and bug reports get convuluted. I've made a list of some of the bigger more specific ones: For high CPU caused by reloading icons over the SNI protocols see: 356479 For high CPU caused by infinite spurious X events see: 373368 For others, search other bug reports here. Hopefully your cause will be fixed in the next or future releases.
OK, understood. One last message, the CPU raise is a process of several hours with a steady increase, starting with 5%, after an hour 15%, 2 hours 28%, 3 hours 35%, 5 hours about 50%, and so on. This is valid for both, Neon and Kubuntu 16.10.
Gerhard, I created a bug similar to yours with more details on what might be causing the gradual slowdown. See bug #380939. I'm curious if this accurately describes the issue you have been having.