Two of my Opensuse boxes where performing really badly, but only some of the time. I tracked this down to the Baloo file indexing program. This is the tool that indexes your files for search, which is useful but only if it doesn’t cause horrendous performance problems.
The symptoms were a very frustrating desktop performance where the mouse would stutter and every few seconds or so, the system would sort of stop and then start again. It seemed to affect all apps to the point where they were basically unusable. It feels like a constant interrupting of the system, which it might well be.
The solution! Disable Baloo using the following command:
Then reboot the system and all will be well. I rarely used the file indexing anyway. It would often crash on its own.