Sorry for the delay, but it took me some time getting a time window for creating a full debug report on highest debug settings as it needed to run for almost 10 hours(!) in screensaver mode(!)...
Log file is available here
About those 10 hours. Looking with Process Explorer, it looks like explorer.exe process is eating more cpu on higher debug settings than no debug at all. No real proof though as the defrag processes get killed on moving a mouse in screensaver mode.
I hope the logging is useful