G5 vs x86?

I've just got my eyes over an interesting article 'bout what G5 and OS X can and cannot do. Apparently, G5 is the most successful processor in the G series (and perhaps even in the PowerPC series), BUT the x86 outstands it (I would say, by far). Mac OS X (Darwin 8.1, Mach kernel 3) cannot compete with it's free adversary: Linux, even they have a little bit of common ground (FreeBSD 4.4 was the model and base for Mach kernel). they are both: 'NIXes.

I can run two conclusions:
1. If OS X is so successful on the client side, maybe these rumors of OS X ported on x86 are not so far from truth after all, and OS X should be even faster than on Mac.
2. If XBox 360 has 3 PowerPC cores it will be, as Carmack said it will be, "about 50% slower than a high end x86 machine). So that's not that good.