have fun changing the processor in the Mac Pro. :)
We grabbed a pair of 2.4GHz Clovertown samples and tossed them in the system, and to our pleasure, they worked just fine. Our samples used a 1066MHz FSB, although we're expecting the final chip to use a 1333MHz FSB, but the most important part of the test is that all 8 cores were detected and functional.
Have fun changing the processor in the Dell, as neither are meant to be hobby machines.
BTW, I've had a lot of PCs, starting with a 486 OEM that through the years and several processors eventually became an Athlon frankenbox (the only thing original left was eventually the keyboard). I have never just switched a processor, as every upgrade came with a necessary mobo upgrade as well.