Dell Mini Tower System manual Power Management, Saving Monitor Power

Power Management

For certain types of monitors and most EIDE hard-disk drives, you can reduce system power consumption by enabling the power management feature. With Power Management enabled, these monitors and drives automatically switch into low-power mode during periods of system inactivity.

Power Management can be implemented at three levels— Maximum, Regular, and Minimum. (The different levels apply to the monitor only; hard-disk drive operation is the same for all three.) The default setting for this category is Disabled.

Saving Monitor Power

If you have a Video Electronics Standards Association (VESA® ) Display Power Management Signaling (DPMS)-compliant monitor, enabling the Power Management category reduces monitor power consumption during periods of keyboard and mouse inactivity.

CAUTION: Check your monitor documentation to make sure you have a DPMS-compliant monitor before you enable this feature. Otherwise, you risk damaging the monitor.

NOTE: The power management feature monitors activity of a mouse connected to the Personal System/2 (PS/2)- compatible mouse port.

By setting Power Management to Maximum, Regular, or Minimum, you can set predefined time-out periods (see Table 2-2) for the two successive monitor shutdown stages, standby and off.

NOTE: Each monitor manufacturer defines the details of the shutdown stages for its own monitors. But in all cases, power consumption decreases with each stage from “on” (full power) to “standby” (reduced power; the display image usually disappears) to “off” (where power con- sumption is minimal). To define these stages for your monitor, see the documentation that came with the monitor.

From either shutdown stage, you can return full power to the monitor in one of the following ways:

•For most DPMS-compliant monitors, any subsequent activity—including moving the mouse— should return full power to the monitor.

•A few DPMS-compliant monitors require that you turn monitor power off and then on again to return to full power.

Check your monitor documentation for information on how your monitor is designed to operate.

Saving EIDE Hard-Disk Drive Power

For most systems, enabling Power Management at any level causes EIDE hard-disk drives to switch to low- power mode after about 20 minutes of system inactivity (see Table 2-2).

NOTES: All EIDE drives shipped with your system support this feature. (For more information on Energy Star systems, see “Energy Star Compliance” in Chapter 1.)

However, not all EIDE hard-disk drives support this feature. Enabling this feature for drives that do not support it may cause the EIDE drive to become inoperable until the computer is restarted and the Power Management category is disabled.

In low-power mode, the disks inside the drive stop spinning. They remain idle until the next drive access, which causes them to start spinning again. (Because the disks take a few seconds to regain full speed, you may notice a slight delay when you next access the hard-disk drive.)

When Power Management is set to Disabled (the default), the disks spin constantly as long as the system is turned on.

Table 2-2. Power Time-Out Periods

Power
Manage-	EIDE Drive	Monitor	Monitor
ment	Spindown	Standby	Off
Setting	Time-Outs	Time-Outs	Time-Outs
Disabled	Never	Never	Never
Maximum	20 minutes	10 minutes	1 hour
Regular	20 minutes	20 minutes	1 hour
Minimum	20 minutes	1 hour	Never

Using the System Setup Program 2-9