Render times - Motion 4 vs. Motion 5

Does Motion 5's 64 bit rewrite offers a substantial performance upgrade or if it's a wash due to relying on the GPU for rendering?

I reached a breaking point over the weekend after a 26 hour render on a :45 spot. I know, strange duration. It was text heavy and it needed motion blur - two of Motion's arch enemies. I searched around, but I couldn't find a comparison between them. Has anyone who made the jump noticed a difference one way or the other?

MacPro 5,1
5870 w/ 2x Cinema Displays attached
12gb RAM (8 more coming soon)
12 core 2.66