|Guide for beginners and administrators|
HW and SW support of power management - if some components are not being used at the moment, they will be turned off or switched to the low-power state.
Lower Micron Process Technology and input - new technologies and progress are bringing smaller components, advanced parameters, lowering the heat and in portable devices extension of battery runtime.
Power-saving modes of the processor - in order to extend the battery life, there are special processors and technologies being put into portable computers. These are able to, in combination with other components and SW support, optimize the performance of the processor, taking into account maximum energy saving, even if a little of the performance is lost. The AMD company developed power-saving features for mobile processors under the name PowerNow!, similar to the SpeedStep™ Technology by Intel. Lesser known but supported technology is LongRun® by Transmeta represented in the Crusoe™ processor. Microsoft in the OnNow initiative, together with support of some functions from ACPI, version 2, implements the Processor Performance Control function into Windows XP and Windows 2003 Server. In short, this function is defined as processor performance control for effective utilization of performance modes of the processor. The performance modes are different stages of the processor, depending on the CPU load and affecting the total performance of the processor and the energy consumption. Details you can find on the Microsoft's sites and in the document called Windows Native Processor Performance Control.
Hardware - BIOS, motherboard and other HW support of APM or ACPI.
Software - the operating system contains drivers and support for power management. The applications are able, in cooperation with the system, wake up the computer (e. g. fax software) or prevent from sleeping (Microsoft PowerPoint and using portable computer for presentations).
User - if correctly understood and used, the power management can largely extend the battery runtime.
Most users do not know much about turning on and off
Stand by mode
PC - Pentium III 600Mhz, 128MB RAM
Measured values of time needed for turning on and off. The values can differ according to the SW and HW (RAM, CPU, HDD).
According to OnNow it should be: 1. Classical start - less than 30s.
2. Return from the hibernate mode - lesser than 20s. 3. Return from the stand by mode - lesser than 5s.
APM, ACPI, OnNow, instant-on
Other tools for diagnostics and configuration
Does my computer use ACPI or APM?
Enable the APM support in the Power Option.
Example: Various BIOS system settings and their consequences for APM
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FAQ (Frequently Asked Questions)