I set affinity on task manager for witcher.exe all I did was do disable core 0 and went back and I noticed the change, before core 0 was always at 100% and the rest of cores were at 0%, but after I dsiabled core 0 I noticed the game is using all cores now, I checked back the core 0 and now the game is using ALL my cpu cores normally line any other modern game.

The effect is not placebo because I noticed with msi afterburner 10+ fps increase, might not be much but the game is smoother.

And I know someone else might have posted this maybe 1 week ago maybe 5 years ago, I just wanted to share the info, because I searched a lot and did not find it.