[code=xorg.conf]
Section "ServerFlags"
    Option        "StandbyTime"        "5"
    Option        "SuspendTime"        "10"
    Option        "OffTime"        "20"
EndSection
[/code]

And add this to your monitor section (and maybe your video card device section):
[code]
    Option        "dpms"            "true"
[/code]

Does Xfce support the capability to power-of the screen after system idles for a while, without any screensaver packages installed?

Regards.