The problem you are seeing is with mutter/gnome-shell being inefficient at frequently-updating software rendered windows. This is a known problem, but until now we only knew of Eclipse triggering it (bug 1756508), and the older pre-Quantum versions of Firefox (bug 1696305).
What you are seeing is a known performance problem, but you have discovered a great test case for it in the Resources tab. So thanks.
As I suspected, this is not a problem with the new Firefox at all (which is hardware rendered). It's a problem with gnome-system-monitor, or any frequently-redrawing software rendered (e.g. Gnome) app.
I only have two more questions: What is your display resolution, and are you using Wayland or Xorg? Both of these can be answered by running 'xrandr' and sending us the output.
Oooh... that makes sense now, thanks.
The problem you are seeing is with mutter/gnome-shell being inefficient at frequently-updating software rendered windows. This is a known problem, but until now we only knew of Eclipse triggering it (bug 1756508), and the older pre-Quantum versions of Firefox (bug 1696305).
What you are seeing is a known performance problem, but you have discovered a great test case for it in the Resources tab. So thanks.
As I suspected, this is not a problem with the new Firefox at all (which is hardware rendered). It's a problem with gnome-system- monitor, or any frequently- redrawing software rendered (e.g. Gnome) app.
I only have two more questions: What is your display resolution, and are you using Wayland or Xorg? Both of these can be answered by running 'xrandr' and sending us the output.