The problem with FPS

[s0kur196]

hi, I'll start right from the case, I'm making a map of size x8, I ran into such a problem when I look at the middle of the map, that is, fps drops from 60 to 30 in zero coordinates, I have already removed all objects from the map and also trees, I also cut everything from the registration, but it didn't help, on the bare canvas of fps drawdown, maybe someone has encountered this problem?