[3.9] FPS dropped in act 7

Hey,
Yesterday I finished act 6 and entered act 7 and my FPS dropped noticeably ever since. I've been playing with stable 60 FPS but now it constantly jumps between 30 FPS and 60 FPS, even while just running on empty map (pic rel). Tried with V-sync off, slightly better but still drops to around 40 FPS at crowded places.



Setup
Intel Core i5 8400
GeForce GTX 1060 6GB
16 GB DDR4 @ 2666 MHz

Temperatures are normal, 50-60'C both CPU and GPU.

Cheers!