John

I was trying to get Windows 11 to run a little bit better on an older dual-core processor system (AMD A9-9425).

Disabling the Sysmain service, as per your suggestion, didn't have any effect on the (slow) boot time. However, it made a HUGE difference with the background CPU usage. At idle, it's now typically single-digits or teens, vs. 70% to 90% previously. Thank you!!