Samsung S7 runing lower FPS than S6

I’m working on a First Shooting Game on GearVR.
I set the screen percentage to 75% , it runs under 59/fps smoothly on S6,
but on S7 it runs only under 30+/fps.

There is also S7 black screen issue when setting the screen percentage to something other than 100%
Here is the fix:

But S7 runing even lower fps is such a shame, Is there anyone facing the same problem ?