I have to admit, I have a fairly old computer that I have to wind-up before I use it :), and I'm thinking of using my bonus in Nov. to get a new one, though it always makes me nervous to actually spend money.  So I'm wondering about this 64 bit thing.  How much of a difference does it reallly make in render time.  I'm no hardware guy, but logically wouldn't a 64 bit computer be twice as fast as 32 bit that's otherwise the same?  Or is it more complicated than that?