I take one audio loop in track 1. then I insert f.e. 6 audio FX on this track. If I am on this track (track is selected) CPU indicator shows f.e. 10% because of level meter graphic on each plugin can be seen.
Then I select an empty track (plugins of 1. track are not displayed) and CPU indicator decreases at 6-7%. If I come back on first track CPU go on 10%....and vice versa
The GUI (mainly plugin's level meters) seems to use a lot of CPU power. It is surprising for me