PCs running Windows 7 to be given turbo boost

Microsoft has tweaked Windows 7 so that it runs faster on machines using Intel's multicore chips, resulting in better overall system performance and less power consumption.

Hardware hooks in Intel's new chips will help Windows 7 deliver performance gains when running applications like DVD playback compared to Windows Vista, the companies said.  The improved performance is accompanied by more efficient power usage, as the OS makes better use of power management features included in Intel's latest chips.

Microsoft has designed the OS to scale application performance by intelligently breaking up tasks like video encoding for simultaneous execution over multiple cores and threads, the companies said. For example, a Microsoft engineer could render a high-resolution image 10 percent faster on a Windows 7 system with a quad-core processor that ran two threads per core, versus a system that ran one thread per core.

The performance improvement depends on the application and usage scenario, said Ruston Panabaker, principal program manager at Microsoft. Microsoft and Intel officials were unwilling to talk in general about overall OS performance improvement compared to Windows Vista or Windows XP.

Most Intel chips included in consumer PCs execute only one thread per core. However, Windows 7 users may see real performance boosts when Intel releases new laptop and desktop chips based on the Westmere microarchitecture that can execute two threads per core. The new chips - respectively code-named Arrandale and Clarkdale for laptops and desktops - will be in production in the fourth quarter this year. The chips will be manufactured using the advanced 32-nanometre process and could reach systems by early next year.

While improving system performance, the intelligent breakdown of tasks could also reduce power drawn by systems, said Mike Angiulo, general manager of the Windows planning and PC ecosystem. Clock speeds of each core can be reduced when tasks are distributed among cores, which makes a processor more power-efficient.

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.