Locks Up CloudReady

I installed Neverware CloudReady on a mini-PC to make a "chromebox" and hoped this would be a solution for a screensaver. It starts fine but after somewhere between 10-30 minutes the whole system locks up (also, very warm to the touch like the CPU is pegged) and I have to hold the power button to shut down and restart. Removed the extension and the system is back to normal.