Fog - Game play very very slow

In Chapter 3 when I move Susan outside the house, she stands in the fog. Then the game play seems to be very slow:
When I press the left or right button, Susan moves only if I press the key for at least ca. 5 seconds. When I press ESC, it takes ca. 5 seconds for the option so show up.

I assume the graphics settings are the problem, the fog is not handled in a good way. How can I change the graphics settings.? It seems that the settings are located in in <GameDir>\acsetup.cfg.
What can I do?

My PC: Windows 10, SDD, 4 GB RAM, i5 CPU (1.7 GHz), Graphics Intel HD 4000.

Best regards
L.

After looking in the internet I found some tips for steam and then also for GOG:

Disable fog/GFX to reduce lag?
www.gog.com/forum/the_cat_lady/disable_foggfx_to_reduce_lag

DeMignon wrote:
To improve performance try this:
- Open winsetup.exe
- click 'Advanced' button
- up RAM limit to 100mb and 'Save' or 'Save and Run'