Game moves as slow as 04 FPS while moving camera around map

I think the issue is the game it's self. I would love to hear otherwise if possible. I have a great desktop computer I never had these issues before I tried everything lowering my settings, going into game files and checking boxes. When I'm in-game It starts out at 40 FPS which isn't normal for me then when I try and go to the edges of the screen with my cursor to move my camera the FPS starts to drop to 20 then when I move it in the opposite direction it can drop as low as 11 then 4! IT DROPS TO 4 FPS ROIT! I don't know what to do I cannot play your game like this please I need a fix, I am not the only one whos having these issues.