I have been giving this a good work out and it's a little gem. Not only does it monitor the CPU, it also allows the CPU to be stress tested, so it allows folks who have O/C'd their system to see if things are stable.viewtopic.php?f=107&t=48568#p487662
I've backported a little terminal program called s-tui that shows graphs of CPU use, frequency, and power consumption in watts--maybe temperature, too, though that seems to not work on my laptop, though I have other monitors that can see the temps. You can also stress load your system to see what'll happen under maximum load, and you can also use indicator-cpufreq on the taskbar to control some CPU speeds (depending on the processor, kernel, and your cpufreq/p_state boot flags).
https://drive.google.com/open?id=1_2nTs ... Ghcg7kLP-8
Though you run it in the terminal, you can click the radio "buttons" with the mouse.
An updated version is at https://github.com/amanusk/s-tui. Would it be possible for this to be placed in the MX repo?