Originally Posted by energyman76b
even with a single core cpu you will not see slowdowns.
If you are in the second session, the first one sleeps. And sleeping processes don't need CPU. Or GPU.
No, a dream from you? RAM
and CPU is always used, same goes for system processes. You can not freeze the whole other session or the other window manager and desktop applications like GNOME and nautilus, X,... running from using the CPU.