Intel used their Smoke engine demo to compare Windows 7 to Windows Vista. The Windows 7 system seems to be able to get more horses on the display, but Intel's point doesn't get across that well as the demo appears to be more choppy on the Windows 7 system than on Windows Vista. If you look closely you can see some noticeable pauses.
See what a difference the new Windows 7 kernel makes compared to Windows Vista. The Windows 7 kernel is optimized for use with Intel core microarchitecture not only does it perform faster it also allows you to put a few cores to sleep while maintaining peak performance.