Insane AS3 performance

i came across this link today, http://www.adobe.com/jp/events/cs3_web_edition_tour/swfs/perform.swf

it’s pretty intense, awsome stuff going on here, I got it up to over 3000 particles and still no performance issues. I kind of wonder what optimization tricks he/she used in the experiment.
Couldnt find the file author though…