Problem with FPS flickering when Oculus Service is running

Even in a normal (non-stereo) BluePrint1stPersonShooter my FPS is oscillation up and down when the Oculus Service is running

The linear up and down jump in FPS is very consistent

If I pause the Oculus Service I get a stable high FPS

In both cases its the standard FirstPersonShooter with BluePrints - I have just added “~ stat detailed”

Any advice on what to do - it’s killing my VR performance, I can’t keep a consistence 75FPS

Just to clearify

I’v change the project settings -> engien -> general settings -> Frame rate
to dont smoote

and I’m running a standalone game from the file manager, the editor is not open

I’m on an Intel i7 with a R9 270