Oculus Performance on Unplugged Laptop

We have a scene that is moderately complex (Unreal Tournament scene).
On my desktop box it runs at 208 fps.

On a laptop (MSI gaming laptop) with the Oculus it runs at 75 FPS when the power is plugged in.
We have disabled battery performance reduction every way possible.
When the laptop is unplugged the frame rate drops to about 40 fps.

This causes the Oculus to lose tracking of some kind. The rendering is at 40 fps but tracking updates are more like 10 fps so the scene appears to jutter quite a bit when you rotate your head.

Weapons hovering on pickup spots do not have the jutter if you hold your head still.

The Stat Unit command shows the GPU to be the bottle neck.
40 fps would be acceptable for now IF we got head rotation updates at 40 fps too.

Any idea how to force the Oculus to deliver full frame rate rotational updates?