It's drivers. Creative is just not going to support and old audigy card well when they can get you to buy their newer products.

This entire article, much like this one that came out just before vista http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html are entirely FUD and have been debunked repeatedly. You can download a copy of windows 7 and test it for yourself.

I installed it myself to see and it uses 100mb or less on my system(vista x64). I also find it faster than chrome or firefox. Though I still don't like the layout of the browser.