XenonS: The offline downloads in GOG tell me that JC2 Complete Edition is on version 1.0.0.2 which AFAIK is the latest patched version of the game.
With my GTX 1660ti 6GB VRAM I chose 'optimal settings' in the Advanced Display Menu, but I reduce shadows to medium.
Plus, I set a 60fps cap with this command line:
Go to properties, shortcut, and then in the "target" add /frameratecap=60 /filmgrain=0 to the end, after the quotation marks.
The filmgrain option is for those who do not like the strange grain the game has during cutscenes. (It's a weird graphic filter which looks really bad on the PC version, so it's best to keep it off.)
The benchmark in-game confirms these settings and the game runs fine on my side.
For those computer systems where the game doesn't recognize the right GPU, you add this command line to the game's shortcut:
Add this command line to your JustCause2.exe shortcut: /dxadapter=0 <<<< will render the game with the dedicated card, check this in the in-game benchmark.
/dxadapter=0 /windowed /frameratecap=60 /filmgrain=0 /aniso=0 /hbao=disable /posteffects=disable vsync=off /fovfactor=1.5 /shadows=off
there is a /failsafe too bad meson won't work--formerly Mesa3D for Windows (I didn't bother, couldn't find a build for windows ), there are also unofficial shader patches... maybe run in ramdisk or play with virtual memory... get a debugger and patch it?
more patches...
maybe limit number of cpu --affinity.