Choose a Power Scheme
By: Arie SlobWindows XP offers a number of power management features that can help you save on your electricity bill. You can choose the length of (idle) time after which Windows will turn off your monitor or hard drive. Windows XP has the following power schemes:
- Home/Office Desk
- Portable/Laptop
- Presentation
- Always On
- Minimal Power Management
- Max Battery
You can make changes to the default settings, and save them either to the scheme currently selected, or save them under a new name.
You can access the power management features from the Windows XP Control Panel under Performance & Maintenance > Power Options.
If you enable power management features, remember that these settings are only for when your computer is idle. When you return to use your computer, simply press a key, or move the mouse, and your monitor and hard drives will come back to life.
There's another issue that's not very clear: If you are using a portable computer your CPU speed is affected by changing the power management features (at least some of the more recent CPU's which use Intel SpeedStep technology). Below is a table explaining how a portable CPU would behave. AC means when connected to an external power source, and Battery means when running on the portable's battery.
|
Power Scheme |
AC |
Battery |
|
Home/Office Desk |
High |
Adapt |
|
Portable/Laptop |
Adapt |
Adapt |
|
Presentation |
Low |
Degrade |
|
Always On |
High |
High |
|
Minimal Power Management |
Adapt |
Adapt |
|
Max Battery |
Adapt |
Degrade |
High: CPU always runs at maximum speed
Low: CPU always runs at low speed
Adapt: CPU speed varies with load (high when busy, low when idle)
Degrade: CPU starts at low speed and performs additional performance reduction as battery discharges
For example, a Pentium III-M processor that typically operates at 800MHz on electric current might throttle back to 500MHz when running on battery power, to save battery life. You might experiment with these settings to see how they affect your battery life, but from reports I've seen there isn't much extra battery time to be gained here.