In earlier releases of Power Management software, inactivity of a system was defined only in terms of the amount of time since the last keyboard or mouse activity. Now, additional aspects of machine activity are taken into account. By default, a machine is considered inactive when all of these conditions apply:
A 1-minute load average is no greater than 0.04
To change the idleness definition from these defaults, see "Changing the Idleness Definition".
Running a screen saver pattern in CDE, other than the blank screen option, may create additional system activity that prevents the system from being idle enough to qualify for AutoShutdown. To enable a system that runs a screen pattern to AutoShutdown at a specified idle time, you may need to change the threshold settings for load average or disk reads.