Seems that every hour, its reporting DWM using high CPU regardless of what I'm doing.
I see those messages logged too. They seem quite bogus to me, almost along the lines of the snake oil marketing that tries to get you to buy this or that cleaner program.
Only time they stop is when the monitors are off (sleeping, i.e., zero desktop use).
For what it's worth, everything is instantaneous, and my System Idle process shows numbers like 99.52% just sitting here running Process Hacker, which refreshes every second, and it might go all the way down to 98.28% idle if I do stuff like minimize/restore windows continuously or move windows around. There's certainly no CPU overutilization.