For on/off movement on Fences CPU load spikes shortly the very moment the mouse moves on to a Fence of off a Fence. This could either be from empty desktop to Fence, or from Fence to Fence.
In order to produce the pseudo-constant high load I demonstrate in the screenshot you have to keep moving the mouse-pointer on/off the Fences, aka move the mouse in circles.
For movement over the empty desktop the load happens for as long as you move the mouse and then drops back down. On the other PC (via Teamviewer) this load is considerably lower than the Fences on/off load, same for the VM. But on my own non VM PC it's just as high as the Fences on/off load, even more so when a higher mouse-polling rate is used (125 vs. 1000 Hz).
Looks to me like Fences is bombarding Explorer exe with some kind of initialization routine (WinMainCRTStartup)!?