In latest 1.17.30.24 I noticed Huge performance drops in Fullscreen mode, I switched to previous Beta versions to make sure it is only happening in latest Beta (and It was)

This might not be the same as MCPE-121850
as I had Vsync disabled (Which was the fix to the report linked above) and also tried different settings in Nvidia control panel for Vsync.

severe performance drop can be seen only in fullscreen mode.

Steps to re-produce:
1. Create a new world on 1.17.30.24 or 1.17.30.25 with a PBR resource pack applied.
2. Turn Ray tracing on
3. make sure you are in Fullscreen mode (other settings such as VSync do not matter, I've tried playing around with these settings & didn't make a difference).
4. Start flying around in the world (fps is far more stable when not moving at all)
5. Observed results: Performance heavily drops
Expected results:
Performance should be the Same or better than Previous versions or 1.17.30.23 Beta 

Other notes: just to do it in a cleaner way, you can first create a world in 1.17.30.23 Beta, play around, look at your frame rates, export world, import it in 1.17.30.24 Beta and start monitoring frame rates again, this is only to have same conditions (all in fullscreen mode)

Important Update: I noticed I can maintain 60 FPS in fullscreen mode too Only if I stand still and Do not move or run or fly anywhere.

As soon as I start flying around I notice frames dropping to lower 30s, which again isn't the case in previous betas.
I updated re-production steps