I don't have a dual Xeon system but I do know that in order for the 2 processors to work you will need to run Win XP as the other versions don't have dual processor support. Also it really depends upon what software you are using with it and if the software has dual processor support. I know for know premiere offers dual monitor support, but only on rendering so there is little advantage gained (it would be better to get a reattime card). Even when exporting in premiere it doesn't take advantage of the 2nd processor, so most of the time its just the collecting dust. I'm not too sure what kind of support the programs you use offer, but if they do offer full support, you will probably notice a huge difference with the Xeon board, but if it offers little support go for the 3.06 as you will see a faster difference with everything and will probably be able to edit faster than with the xeon board. I did alot of research on this when i was looking at a new system and thought 2 processors would be much quicker than 1 but learned that for me anyways (due to the software I use) 1 faster processor will do more for me than 2. Good luck with your choice, I'd definalty research the support of my software and see if its worth it.