[Bush2000]

I don't recall PC users being able to do the equivalent of bumping a system from a single G3 300 to a Dual G4 500 without scrapping the mobo.

Get real. I can buy a dual proc motherboard and only put a single CPU in it. And then upgrade the processors at a later date.

[dheretic]

You conveniently ignored the point, Mac users do not have to buy a new motherboard.