Both “service host local system” and “compatTelRunner” are used for windows update. They use up lots of resources for only checking the compatibility of windows update, especially from 7 to 10
Disable them by following steps:
- service host local system high usage
disable superfatch in services.msc
- compatTelRunner
taskschd.msc > Task Scheduler Library > Microsoft > Windows > Application Experience > disable "Microsoft Compatibility Appraice"