I can NOT recommend the KDE plasma widgets

[EssayAmEye]

I was interested in monitoring CPU usage, so I enabled the KDE CPU monitor widget.  It seemed OK, but then lag started occuring.  Then I opened it and turned on monitor all CPUs.

In short, never do this Apparently, the default interval is set to 0 seconds, which can't be changed from desktop, and if it monitors all six CPUs, it overwhelms the buffer with monitor requests, which the processor is too slow to respond to.  Your user desktop will crash, and from GUI, you will be able to do nothing at all.

Later, I'll follow up how to resolve this of you get stuck - from the GUI, you can log into root and edit a file in the .config, to remove all those extra CPUs.  I don't have a good Internet connection right now, so I'll post when I do.

Until then, treat those widgets gently.  It seems at least one of them can't be tolerated by the hardware.

I'm glad I'm not the only one who was caught by this. I had the same issue!