Since Firefox has this newfangled performance analyzer (about:performance) I just gave it a spin. This is my setup:
Firefox 64bit @ SSD
I started Firefox and gave it 60 seconds to completely load all pages and go to "rest".
This is the result:
Somehow, Ubiquity always seems to claim a minor amount of CPU, despite the fact that I had been idling for about a minute when I took the screencap. What is your experience? Do you think this is just error of margin in the performance measuring process? Or is Ubiquity using 1% CPU at all times, no matter if it's just idling in the background? What could be causing the constant CPU usage?