Its not entirely marketing though, AMDs A64s actually do give the same performance as an equivalent intel of the same rating. ie an athlon 64 3500 gives you close to the performance an intel running at 3.5 GHz would. Even better the damn things overclock like crazy, my 3500+ is supposed to run at 2.2 GHz, but i use it at 2.8 GHz on air cooling without any problem. Thats an AMD 4400+ for the price of a 3500+ !

Too bad intel's core 2 duo/quadros tromp them in the multicore version...