Well to get back on topic my first test results on snow leapord:
late 2008 8 core mac pro
8800 gt
ocz ssd
cat 167

using 720p files.. all around 150mb in size snow leopard allows for 1-2 more layers to be run... total of 7

I would say that so far it is a verifiable improvement... will test LFG cards next week if nobody beats me to it.