Turbo boost pressure wrong when PC is at its limits

Soo...
I have this super weird problem of the Boost pressure of Turbos being wrong when my PC is under a lot of stress.
For example on some of my Automation cars, i can sometimes only get 0.2 or -0.2 bar of pressure on a map with stuff on it, although it should go up to 1 bar and above. This is decreasing the cars power by a lot and is really annoying, because my PC isnt really that good..might need a new Graphics card

But when i go on an empty map, such as grid,small,pure , My cars work perfectly fine.

Also the Boost pressure is never consistent. Its always twitching around in an area of a few 0.x bar

 

This game works best with 60fps, if you get below 30fps as CPU limitation you might get really weird behavior.

 

The simulation is very intensive and even at 30FPS I've seen some strange behaviour. Best you can do is tune the whole system for highest performance possible so you don't have these issues. I've seen the turbos do the same on the occasion the game drops under 30FPS myself, though I've not had it happen very much as I have a stronger machine.

If you don't mind me asking, what's your computer's specifications?