Microsoft has published a 14-page white paper titled "Win7 Power Management", which describes how Windows 7 is reducing energy consumption by providing a brief overview of the 14-page white paper:
Energy consumption of idle resources
When a computer is started, it will not always be in full load running state, so there will be a lot of free time, so the power consumption in the idle time becomes an important technology. In Win7, idle power consumption is effectively improved, when a certain hardware time does not work will enter the Low-power state has reached the purpose of saving electricity. This technology is included in the CPU, hard disk, memory, and network sections. For example, a full power run power consumption of 35w CPU in idle power consumption of almost 0, only this one can save a lot of electricity.
Adaptive Display Brightness adjustment
Microsoft says it usually shuts down automatically for 10-15 minutes without any action. But in actual use there will be more short time operation, in order to better save energy, the technology will reduce the brightness of the display. In addition, it can use a number of sensor devices, depending on the ambient brightness to adjust the display brightness.
To start a service by triggering
Typically, system services are started together when the system is started, and then reside in the background to wait for calls. In Windows 7, some system services are started only after some events have been triggered, such as inserting a device or changing IP. This can reduce the number of long-running services in the background process.
Enhanced Processor power Management
Win7 integrates the latest power management technology, which enables Windows 7 to dynamically tune CPU performance based on current load conditions and performance requirements.
At present, the processor uses the gap free time of processing instruction to achieve energy-saving purpose, but most energy-saving technologies require a certain length of idle time to obtain energy-saving effect. This technology increases the processor's idle time by letting the Windows kernel terminate at the same time and focus on the more dispersed timers over a short period of time. In addition, when a laptop is using a battery, Win7 reduces the activity frequency of non-critical background programs.
Power improvement of network equipment
The compatibility of the low power mode of the wireless network controller in Win7 is enhanced and is enabled only if the wireless AP device supports low power mode. Vista can cause a sudden disruption to wireless network connectivity because it does not detect whether it supports low power mode in advance. Win7 prevents this from happening and detects whether the wireless AP supports this mode before entering low power mode.
Low Power Audio
Win7 will support Intel's Low-power HD Audio specification, which allows the codec to enter a very low power state. Win7 also supports selective suspend technology, which shuts down devices that are idle, such as USB devices such as microphones and cameras.
Optimization schemes for typical applications
In addition to the improvements listed above, Microsoft has turned its sights on specific applications, including search, browsing without networking and games. Here are some of the optimization scenarios for DVD playback:
Keep the CPU low power mode without impacting playback performance
Improve the power consumption of the Desktop Window manager and GPU by changing the architecture
Intelligent data caching can reduce the speed of optical drive