By default, when users log in to the desktop environment, a splash screen is displayed. Icons are displayed on the splash screen while the user logs in. You can turn off the splash screen to reduce CPU usage during login.
# gconftool-2 --type bool --set /apps/gnome-session/options/show_splash_screen false
Alternatively, users can choose Applications -> Desktop Preferences -> Advanced -> Sessions, then deselect the Show splash screen on login option.