The Graphic User Interface is very useful but it consumes a lot of CPU power.
In many cases the GUI is useless so I disable it.
With Ubuntu 14.04 you can disable the startup of the GUI at boot time, simply changing the grub configuration.
Open a new terminal.
Make a copy of the grub file, so you can restore your previous version…..
# cp -n /etc/default/grub /etc/default/grub.orig
Edit the grub configuration file with your favourite text editor (I use vim…)
# vim /etc/default/grub
Comment the line containing the GRUB_CMDLINE_LINUX_DEFAULT declaration by adding a # at the beginning of the line, you shoud have something like the following:
Change GRUB_CMDLINE_LINUX=”” to GRUB_CMDLINE_LINUX=”text”
Uncomment the line
removing the # at the beginning.
Save the changes and exit from the text editor
Udate the grub
Reboot your system.