I would like to make KDE startup faster; I noticed that there are many applications that run on boot, that maybe I don't really need. Where could I go and change that? (safely)
You can try to go to "System Settings" and under the "System Administration" go into "Startup and Shutdown"; here you have a certain degree of control on what should be started on boot. Be sure to navigate all of the three tabs because each one contains a different set of possible startup apps and services.
You may find this a useful read: http://userbase.kde.org/System_Settings/Startup_and_Shutdown
You can also try to go into the
~/kde/Autostart/ folder and delete the links to the applications that you don't want to start at boot.
Hope this helps!
There are tons of posts about this topic but the developers acknowledge there is a lag in the startup process, look at this bug.
My tips: use preload, disable unused services (cups, nepomuk, bluetooth), system startup is improvable but starting KDE is the elephant in the room, there is no silver bullet for this.
The best I could do is activating the automatic login in kdm and when I power on the pc it starts and doesn't stop until fully operational.
Change this in /etc/kde4/kdm/kdmrc
[X-:0-Core] AutoLoginEnable=true AutoLoginLocked=true AutoLoginUser=YourUser