Sudden framedrops. (Advice needed)

[SO•Marty]

Hey everyone,

The last few weeks I experience sudden framedrops when playing LFS.
It happens on multiple tracks, and it seems random when they occur.
The frames drop from 40+ fps to 6-7 fps, the sound of LFS judders as well when this happens. After 10-15 seconds the issue resolves itself and in the blink of an eye the framerate resolves itself back to 40+ frames.
I have been checking the settings, turning the Anti-Alias down/off seemed to have solved the issue, but I find it confusing since it happened all of a sudden, and I cant find a real explanation for it. I have the AA set at x8 for years, and never had an issue with it.
Temperatures of my pc stay the same, and doesnt overheat at that moment.

Here are my LFS-settings:


I hope some knows what might be happening, thx in advance.

Marty