Microsoft has made some kernel changes in Windows 7 to improve the power management of cores on Intel's chips compared to previous operating systems. A demonstration showed the power drain during DVD playback on a battery-powered Windows 7 laptop of 15.63 watts, compared to a drain of 20.48 watts on a similar Windows Vista laptop. Such power savings could improve battery life of a laptop by hours, Panabaker said.
Microsoft also makes better use of a timer system that puts cores in Intel processors back into sleep mode when idle. Depending on usage, the OS can intelligently put different cores into different power states, and processors remain in idle mode for a longer period in Windows 7 compared to Windows Vista, Panabaker said.
Intel's Westmere chips will also feature new onboard instructions for AES (Advanced Encryption Standard), which gives hardware instructions to speed up encryption of data, said Mark Swearingen, director of Microsoft program office at Intel. Microsoft has added the AES instructions to the Windows API (application programming interface) so application developers can build programs using the feature.
One program that takes advantage of on-chip AES is BitLocker, a Windows 7 feature to encrypt data in a system. Typically disk encryption and AES-type functions have some CPU overhead and new instructions help to reduce that overhead, Swearingen said.
Another feature included in Windows 7 that takes advantage of Intel chips is XP Mode, an environment that allows users to run Windows XP-compatible programs. The technology uses Intel's on-chip virtualization technology, and it is particularly useful for small businesses that need a safety net to run legacy applications. This feature is also supported on AMD's AMD-V virtualization technology, which comes with most AMD chips.