Check out this article over at anandtech about swapping out the new dual dual core xeons with dual quad core ones due out later this year.

http://anandtech.com/mac/showdoc.aspx?i=2832&p=3

8 cores, upgradable from 4 cores if Apple doesn't do something to forbid it.

That's cool. But I still stand by my decision to buy a Power Mac G5 Quad in case there are any 1st Generation issues with the Mac Pro, like the Mac Book Pros.

heath