GDM3 Speed up disable Wallpaper and Zoom

GDM3: Change Wallpaper Change background color Speed up GDM3 after boot

Problem: By default Debian with GDM3 is slow on older Hardware like Laptops or PCs with small Graphic Card

Background: GDM3 shows Images at size 800×600 an zooms up to Screen Size, this burns speed.

Solution: edit gdm3-theme config

sudo nano /usr/share/gdm/greeter-config/20_debian

and change to

#Use a specific background
#/desktop/gnome/background/picture_filename     /..path #to wallpaper
#/desktop/gnome/background/picture_options      zoom #zoom
/desktop/gnome/background/primary_color #357DAA  # color Win2000 

# Theming options
#/desktop/gnome/interface/gtk_theme             Clearlooks

# Greeter options
#/apps/gdm/simple-greeter/logo_icon_name        debian-swirl

# Play system beeps - especially the one when the greeter is ready
#/desktop/gnome/sound/event_sounds              true

# Some other possible options
#/apps/gdm/simple-greeter/banner_message_enable         true
#/apps/gdm/simple-greeter/banner_message_text           Welcome
#/apps/gdm/simple-greeter/disable_restart_buttons       false
#/apps/gdm/simple-greeter/disable_user_list             false

# The lower panel doesn't work with the compositor
/apps/metacity/general/compositing_manager              false

# Prevent the power management icon from showing up
/apps/gnome-power-manager/ui/icon_policy                never

Additional Info:

Install “metacity” window manager its needed by gdm3 too on openbox or LXDE Desktops

If “desktop-base” is not installed the gdm3 background is shown lime green then create a empty file named

sudo nano  /usr/share/gdm/greeter-config/10_desktop-base