Microsoft Enhances Power Management in Windows 7

One thing that Microsoft is doing is sharing telemetry data from its Windows 7 beta users with its partners, Leznek said. If there is some incompatibility between the hardware and software—for example, if a USB device interferes with a software feature—Microsoft and the USB device maker can work together to resolve the issue.

Microsoft also is working with partners to ensure that the same specifications are being used by everyone, Leznek said. For example, during the development of Windows XP, some vendors used the term "sleep mode" to describe when the system wasn't being used, while others used "idle."

The energy management features in Windows 7 revolve around not only finding ways to reduce energy consumption, but also to improve battery life and give IT administrators and Microsoft partners tools with which to better troubleshoot and handle power management issues. Windows 7 also will give IT administrators greater granularity in their group policy settings

Windows 7 will come with improved Trigger Start Services. Systems services tend to start automatically and run in the background, waiting for an event to happen to be put into use. Prior to Vista, the systems services could be turned on or off. With Vista, that was improved to having the systems be delayed.

With Windows 7 and the Trigger Start Services feature, the system service will start only if an event starts it.

"If you don't have a Bluetooth device running on the machine, why have the Bluetooth service turned on?" Leznek said.

One of the tools for reducing power usage when a system is idle is what Leznek called "Adaptive Display Brightness" for system displays, which can account for as much as 40 percent of the overall system power consumption. Before, when a system was left idle, the display would go black, which he said users found frustrating. With Adaptive Display Brightness, the screen dims but doesn't go completely black when the system is idle for only a short time.

Windows 7 also will reduce power to the wireless NIC (network interface card) when the system is plugged in, or to the wired NIC if the system is running wirelessly. In addition, when the user disconnects the network cable, the OS can place the network adapter into a low-power state, and will put it back into a full-power state when the network cable is reconnected.

The ability to put wireless network controllers into low-power modes also was available in Vista, but because few wireless network controllers support the low-power modes, it caused the computer to disconnect from the wireless network. That support has improved since Vista came out, Leznek said. 

In addition, during times when the system is idle, Timer Coalescing enables Windows 7 to execute various background activities at the same time to keep the processor idle for longer periods of time. Windows 7 also will defer noncritical background activity when the system is on battery power to extend the laptop's battery life.

Next: Flexible Energy Management >>