Funny, I’ve had the opposite feeling.
My PC is a four year-old Razer (which was 2 years-old when the sim launched) and it has lost performance with SU9. It’s stuttering, has erratic FPS and the fans howl like a banshee.
I’ve read a number of threads where PC users are having to lower LODs to get the sim back to where it was performance-wise with SU8.
My experience on the Xbox Series X continues to be way better.
However, I know there are many Xbox users who are livid with how the sim is performing now, too.