I recently built a web server in OSX as well as in Debian x86 on two very similar machines. iBook G4 and an Athlon 1ghz. My guess is that an 800mhz ppc processor is roughly equiv is raw performance to ...

Not from an academic point of view. Sure, you didn't know what hardware to buy next, but it did tell you a whole lot about OS X's kernel, GUI overhead etc. which I wouldn't call irrelevant. It would ...