Quote - Exactly the comparison I was looking for..thanks! Are you operating on 64 or 32 bit pc?  I'm on 32. Anyone know if it's possible to run 32 and 64bits on the one pc? I was thinking of upgrading to 64 but my 'puter guy warned me that lots of software won't work on 64bits. 

I run Poser 7 and Poser Pro on Vista 64bit with 8GB ram and a 4 core CPU. The main reason for me to go for a 64bit version was the 3GB ram limit for the 32bit version. My scenes tend to be big and Poser would crash while rendering on a 32 bit system when I ran out of ram.

I also heard about all the 32 bit programs would not run on a 64 bit system, but there was only 1 video editing program I couldn't run and my old powerDVD 4.0.
But these programs runs fine on a 64bit system:
Pegasus, Clothes converter, texture convertor 2 and MorCloth when it comes to programs for Poser.

You can install Vista 64 on top of XP 32 and have a multi boot if you want - or was it the other way around ? Can't remember. But I did had a multi boot first just to have a "backup OS" if the other one should fail. But now I only have Vista 64bit installed.