For one thing, benchmarks should always be taken with a grain of salt, particularly those which span platforms such as Apple's G5 vs. Pentium/Xeon comparisons. They often don't reflect real-world performance -- which is why Apple has presented application comparisons for Photoshop, QuarkXPress, Quake 3, Mathematica, and several other popular apps.
The result? The G5 puts the smack down on the competition. Hard
Regardless of whether the SPEC numbers may have been boosted on the G5 because Apple used an optimized compiler on the G5s and didn't do quite as good a job of optimizing on the Windows machines, the huge performance advantage seen in real-world applications makes this all but totally irrelevant. Not to mention -- many well-known developers have pointed out that benchmarks like SPEC are focused heavily in the CPU(s), and don't take into account very important real-world factors like the G5's 2x1GHz frontside busses, Serial ATA hard disks, built-in Gigabit Ethernet, HyperTransport interconnects, etc...
In short, I'm ignoring the nitpicking, the whining, the envy, and the sweat-soaked, hand-wringing fear that has taken hold of some of the less reputable Wintel pundits.
