Just about to get a new machine, but had a few things that need clarifying.

I have VUE7i. 
Is rendering still handled by the CPU only?  Looking to get i7 920. 
Do any of you have experience with dual graphics?  Does it make a difference with VUE?   Looking at single or dual ATI 4870.  Any suggestions for graphics cards?

This is a sizable purchase and I've just about made up my mind. 

There are many articles about gaming rigs, but few about 3d animation rigs.  I assume they would be similar, but still am not sure.

Thanks for any advice.