Hello here is a small instruction how to solve the problem with fps...first download the HD package :

https://steamhost.cn/app/311670/

i noticed when you start the game with settings on ultra you will have low or fps drop, but if you want fix this watch the video

instruction:

-in video options turn off Vsync and put Max Fps to No Limit
- every time you start the game go to advanced settings and apply the auto config
- launch the game
- agan go to advanced settings and apply Ultra settings without :

Depth of Field
Order Independet Transparency

and put Shadow Quality to Medium