|
Saving our customers time and money while saving the Earth, one system at a time. |
 |
Enovative Energy Solutions |
|
|
|
Home -> Resources -> Twenty-One Green IT Tips -> 6. Enable Computer Power Management
6. Enable Computer Power Management Microsoft Windows supports Power Schemes, which direct the operating system on when to shift to a lower power state. Power schemes are enabled from the system Control Panel: click on the Power Options icon. Power Scheme Settings Each Power Scheme setting describes the amount of time that the system waits before taking a particular action. Such settings are commonly called "timeouts." The most important settings are the ones for System Standby and System Hibernation. These can yield some significant power savings because very little power is used in each of these two states. What Is System StandBy? In System Standby, the computer is in a light sleep. There is still power being used to refresh RAM and to run the CPU, but all devices are in the lowest possible power state. The benefit of System Standby is that the system can wake up very quickly. Web search:  System Standby Issues with StandBy Mode One potential disadvantage of this mode is that the contents of RAM are not copied to disk. This means that if power is accidentally lost, then whatever has not been saved to hard disk will be permanently lost. Another issue with StandBy mode is a potential security risk. The risk is applicable for laptop computers with hard drive encryption. This includes third-party encryption solutions as well as Vista's BitLocker drive encryption. Hard-drive encryption can be defeated when a computer is in StandBy, because the encryption keys are in RAM. A group of researchers at Princeton University demonstrated this in 2007, using a can of compresed air. The research report, with a link to a YouTube video, is here: Cold Boot Attacks on Encryption Keys. What Is System Hibernation? In System Hibernation, the computer is in a deep sleep and everything has been turned off. Before entering this power mode, the entire contents of RAM are copied to hard disk. When you enable this mode, the system sets up a file that is the same size as system RAM. The file is named hiberfil.sys, is a hidden system file. Web search: System Hibernation
Plugged In vs. Running on Batteries There are two sets of setting, one for when the system is on wall power and a second one for laptop computers that are used when the system is running on battery power. Set up the batter-powered settings to allow the desired system behavior (whether long battery life, or no power management for presentations). And make sure to set up the Plugged-In settings so that the system can shut down and save power during a period of inactivity. |
|
|
(C) 2010 Enovative Energy Solutions. All rights reserved. | |