The most important changes happened the last year and starting this year with the x264 development. While you would expect they would optimize for the new i7 platform, they also did this for the new Phenom II. And the results speak for itself. It's the first time AMD can keep at the same pace as any Core 2 Duo/Quad. So software-optimizing does matter, but there are no other programs we are aware of they do optimizing for AMD, as you can see with CineBench R10.