kdeplasma
I am aware that the shortcode of "Shift + Alt + F12" disables all the desktop effects of Kubuntu 15.10. However, is there a way to disable all those effects automatically and permanently in every future session?
Objective: Speeding up Kubuntu 15.10 as much as possible.
Found a way for KDE 4 (up to Ubuntu 14.10). For modern KDE 5 see other answer.
Go to System Settings → Application and System Notifications → Manage Notifications.
Select Screen Saver as the Event Source
Locate and select the Screen Locked
add this command to the event:
xset dpms force off
It will turn off all displays every time it gets locked.
Best Answer
Head to
Remove ✔ mark from Enable compositor on startup
When this is done, make reboot.