FPS drops on approach after about 2.5 hours?

As you know I stream MSFS quite often. After about 2.5 hours of streaming the FPS drops to about 5 FPS on approach!
It appears to be a weather loading issue from what I hear. My PC is high spec. and I have no issues with internet bandwidth.

Does anyone have any up to date ideas about this?
GripperSim. : )

Moved to #community-support:tech-support.

Just about to land into Toronto with PG on, FlyTampa YYZ and SamScene3d

3hr45m into flight. Still at 45FPS.

Will report on the ground.

Landed just after 4 hours in the air, no FPS drop.

Running on Ultra, 200LOD, 4K.