Hi! 
At the beginning I would like to apologize for my English. 
Ok, so... I have a problem with FPS. Sometimes my FPS drop from 90 (?) to 1 or 15, and i have to exit the game, because i can't fix it in any way.   
My hardware: 
I7-4770k 3.50 GHz 
8 GB RAM 
NVIDIA GeForce GTX 1050 TI 
System type 64 bit