Oh dear, we're comparing main specs again.
The quality of the motherboard matters more than anything else.
It's all very well having tonnes of horsepower if you can't put it down on the road, as I discovered with my Dell. Fantastically fast CPU, fast hard drives, but overall the machine isn't as fast as the equivalent G5 (single 2.5 GHz) by a huge amount. That's mostly the hardware (it's got the world's worst motherboard, not what you'd expect from an at-the-time top of the range £1500 machine), but I reckon it's also partly down to the OS. And Vista is
more CPU consuming than XP!
No more PC stuff for me please, fed up with all the junk that's out there...