still havent gotten an answer though..
does anyone know or have any idea the possibly percentage increase in speed with this new mac pro?
I'm only making a guess, so don't take it too seriously.
For non threaded apps that aren't memory intensive, say 20 - 30%.
For threaded/memory intensive apps, say 30 - 50%. (Presuming all memory channels used).
The memory bus seems to offer the greatest performance advantage, provided your apps can use it. Newer OS's like Snow Leopard and Windows 7 will hopefully further improve performance, provided they deliver as promised.
I'm still waiting for some concrete numbers myself.