Cubase 10, Windows 10 and multi-core (14+ cores)

Cubase meter shows ~100% Average load continously, and 50-60 RT load when playing back
10 (20) Cores seem to be working b/w ~20-40% each in task manager


I made another weird observation: freezing one single track (Omnisphere 2.5) in this project does the opposite of easing the resources. The project becomes unplayable (only dropouts, i.e. will not even playback something, meters only flicker). Maybe any hints on this?