You should make every effort to find out what's causing that to happen. What does Task Manager say is causing it ('Processes' tab, 'Description' column)?

Have you downloaded any other new program before this started?

Try uninstalling and re-installing - unless you've already done that. 

Also, if you haven't already done so, start a trouble ticket with support@stardock.com . Then don't write again to them until you hear from an actual person as doing so will kick your email to the back of the queue.

Fences writes a log constantly while running.  Every hour it trims that log to keep in manageable but saves the last hour in case you need to send it to SD for debug/fixing.

In the "About" tab in Fences config window (right click on desktop) you'll find the "Report a problem button". It'll make a copy of the debug file from the last hour (so do it after one of these episodes of spiking CPU) and attach it to the email you send to support.   Screenie below shows what I mean.