If You Want A Performance Increase... (You probably don't know about this)

I use Windows 10. You can check to see if your cores are parked using the resource monitor. When I run in high performance mode, none of my cores are parked. However, I'm using an Intel CPU. Maybe it's different with an AMD CPU?

Edit: I'll add that Sims 3 runs better than Sims 4 does on my machine so it wasn't really a concern for me anyway.