SR3 renders faster than ever on my machine. Textures load faster, not much in the way of crashes so far, and pretty much everything seems to work better now.

But make sure you have the latest drivers for your system, especially graphic display. That definitely helped me.

And my OS and Poser 7 install were very fresh and uncluttered when I installed SR3. Don't know if that had anything to do with the good results or not, but just thought I'd mention it.