I thought I posted this already but I can't find it. Apologies if this is a double post.

Simple question, I think: I have two Xeon 3.4Ghz processors. I'm considering upgrading to a CPU with two quad 3Ghz processors. By my logic, that would mean processing speed of better than 3x what I have now... meaning rendering times and export times of about 1/3 what they now are.  Can someone check me on this?

Tough one.. really depends on the application, how well it takes advantage of multi-cores. The other thing is memory. You need to be running a 64bit OS to take advantage of more than 4 gigs ram, which the processors you are considering can leverage. Generally, high clock speeds show more gain dollar per dollar than more cores.