v1.9 frame timing not stable

While performance has never been great previous to v1.9 I had been able to have a mostly stable framerate with adjusted settings and lower render resolution.

Since the 1.9 update the frame timing seems to have changed and there are now constant micro stutters even when the gpu is not maxed out.

The gpu is busy for sure but it just never settles almost like the frame delivery / timing / pacing is being interrupted causing late frames to get dropped by the vr compositor.