Is there something so hella-fantastic about the 8-core that the prices to upgrade a CPU are so much more, relative to the quad-core? Look at these screen shots: on a quad-core, if I wanted to upgrade to 2.93GHz the cost is an additional $400, but on the 8-core it's $2600 (2 x $1300). You know, I keep hearing how the Mac Pro is for "pros, so the cost doesn't matter so much" -- that is simply not true (and mildly offensive). Just because I happen to need more "power" to do my work doesn't mean that I have money leaking out of my pores.... au contraire mes amis! Can someone tell me if there's a logical reason why there's a $900/CPU difference in upgrading an 8-core vs. a quad-core Mac Pro?