I installed the game after several months.
No HW changes, no settings changes (saved from previous install), newest drivers for both windows and GPU.
I installed the game, benchmark 60 - 70 fps. All good. Settings ''Medium'' to ''High'', like I played dozens of hours without issues before.
During the middle of some random small battle game started to lag. Now when I run benchamark my FPS NEVER goes beyond 30.
Doesnt matter what setting I use. High - 20 FPS, All Low and AA turned off - 18 - 27 FPS
I never had these issues before with this game and I am kind of clueless what to do. I am trying to fix it for two evenings with no effect.

CPU: i5-2500k 3,30 GHz
RAM: 16 GB
GPU: Nvidia GeForce GTX 760

I know hardware isnt TOP, but like I said, few months ago I played the game on Medium to High settings while getting up to 70 FPS.