When there is big non interactive software running and if I required more processing power then, after removing the desktop screen does kernel stops processing related to GUI(graphical user interface) so that CPU can focus on other stuff.

I am assuming that If we don't have external graphics card then, processing related to it handled by cpu. Correct my assumption if I am going wrong.

If I am wrong then, how GUI is managed? And what type of processing done by CPU?

  • No idea, but some clues: Try using xset dpms force off to turn off the display. That might tell the OS what's going on while just removing a display might not. If you understand enough about how things work (I don't), then strace can be used to see exactly what a command or system is doing under various conditions.
    – Joe
    Commented Jun 10, 2016 at 21:11

1 Answer 1


I do not believe that disconnecting the monitor will influence performance, and, no, it won't stop the GUI from running or otherwise using resources. Graphics elements still require GPU or CPU (or both) to be manipulated, even if there is no device attached to display it.

You have several options to stop the GUI on a booted system, depending on your Linux distro's version, however:

  • In a pre-systemd system with SysVinit, switch to a 'runlevel' that does not include the GUI. On many systems, this is runlevel 3, unless it is a systemd system, like so:

    $ sudo init 3
  • In a systemd system, this runlevel switching behavior is emulated. The runlevel can be changed to the equivalent of 'runlevel 3' like so (may differ depending on distro, check refs at the end of this answer):

    $ sudo systemctl isolate multi-user.target

(to undo this: $ sudo systemctl isolate graphical.target )

This is my thinking for a server that is already built, in service, and is a 'special snowflake' that cannot be easily replaced with a configuration that does not include Xorg, GNOME, QT, GTK, etc. (aka GUI) components. If I were able to, I'd put this system on a "to be rebuilt" list of machines that should not have GUI libraries and applications installed. :)

To stop the GUI from loading at boot, in SysVinit, type

 $ man 5 inittab

or for Systemd, you'll want to peruse the references I list below to also see how to disable the GUI from starting at boot.

Refs: https://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet https://www.freedesktop.org/wiki/Software/systemd/FrequentlyAskedQuestions/

  • Anythinig wrong with this answer? :/ Commented May 26, 2017 at 19:06

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