powercfg will indeed report on what programs have raised the timer interrupt frequency. However powercfg (and clockres) both just report on the state at a moment in time. Many programs repeatedly raise and then restore the timer interrupt frequency and powercfg utterly fails to understand this. And yet, powercfg is the best that Microsoft has supplied.

I eventually decided to write a better alternative. The batch file below (requires Python and Windows Performance Toolkit to be installed) will report on all timer interrupt changes by all processes over the time period recorded:

https://github.com/google/UIforETW/blob/main/bin/trace_timer...