I think I enabled an MS service that is throttling cpu 50%+ (how to disable)

I recall enabling some sort of monitor/feedback to MS service after or during the update from win 8 pro to win 8.1 pro. But I dont recall what it was called.

Now my cpu is running 50%+ much of the time for no apparent reason.

Windows Host Process Tasks .... or some such thing shows in the Task Mgr when it is throttling my cpu....and runnig it 50%+.

How can I find and disable the service that is causing this?

Thanks.