News

Microsoft Touts Power Management in Windows 7

• By Jim Barthold
• January 08, 2009

Echoing Ballmer, Microsoft's "Engineering Windows 7" blog took up the cause, with a post on Tuesday about how Windows 7 will improve power management for devices.

Dean DeWhitt, a member of Microsoft's kernel program management team, wrote that Microsoft's goal is to devise "energy saving opportunities" in Windows 7, starting with the power policy settings. One feature in Windows 7 is an enhanced sleep-idle feature for the computer's display, which typically consumes the most power in a laptop PC.

He estimated that "the display can consume approximately 40% of the power budget on the typical mobile PC and anywhere from 30-100+ Watts on a desktop PC."

The Windows 7 team is also addressing the power use of processors, which represent the third most power-hungry element of a PC after chipsets.

"When the system is mostly idle…there is no need to be running the processor in the maximum performance mode [so] the processor voltage and frequency can be reduced to a lower value to save power," DeWhitt wrote. "Similar, the hard disk drive and a variety of other devices can be placed in low-power modes or turned off completely to save power when not in use."

Microsoft is building on its previous investments with the Windows 7 device power enhancements, DeWhitt explained.

"We have made several investments in the area of device power management including enhancements to USB device classes to enable selective suspend across a broad range of devices including audio, biometrics, scanners and smart cards…[to] enable more energy efficient PC designs," he wrote.

The investments also extend to improving power management for both wired and wireless networking devices, he added.

End users can take advantage of an "inbox utility" in Windows 7 that reports the energy efficiency of the system in HTML format, listing the top-10 power problems, DeWhitt explained. The utility can be accessed by running "powercfg /energy at an elevated command prompt," he wrote.

For Windows 7 developers, Microsoft offers its Windows Performance Toolkit to track resource use by applications. The toolkit helps to resolve bottlenecks and energy efficiency issues, DeWhitt explained.

In addition to the rollout of Windows 7 Beta, Microsoft announced a Windows Server 2008 R2 Beta release on Wednesday. Both Windows 7 and Windows Server 2008 share the same codebase kernel.