I have seen a big drop from time to time when my mouse pointer is over the flight sim screen. When I move it over to another screen, the fps pops back up. Doesn’t happen all the time, just periodically. The range of change is from 30-40 fps down to 2-7 fps. I have an i9-9900K, 64GB ram, SSD, RTX2070S.This seems to happen most often while on runway ready to take off, but it occurs in flight too. It could be runway vicinity related, but I haven’t really tied it down.