AFAIK, Windows is not optimized at all for it, and MSFS neither. Normally this happens only in consoles, because it’s easy since all have the same identical processor.
Playing with afinity I have reached to make some Matlab workflows 4 times faster in a 4 core machine.
It’s very dangerous playing with it, becaise you can make a process starve and instead of improving, you’ll get worst results, but sometimes it can make you improve a lot.