Problem on Pimax 8kX with Smart Smoothing

[Eisprinzessin]

Hi there!

With my settings im on 55-60 FPS. But when i enable smart smoothing to lock it on 45 i have judder when i turn my head. 

Interessting stuff: If i go out of window focus (so lets say switching via Alt-TAB to another programm) DCS runs completely smooth in my Pimax HMD. Locked to 45fps budder smooth headmovement (game is not paused, plane flys straight). Everything look super nice, even head movement. But when i click it back to focus, i have the jidder again, when i turn my head. Even i have no drops unter 45 fps (ctrl+pause)

Next strange thing: If i activate smoothing on steam VR it does nothing. Even in PITool it is deactivated....i force it to always on, it stays on 55-60 fps.

Any ideas?