As a matter of fact, it should put even more distance between Northwood and the Athlon XP.
It's all marketing. Since the Northwood @ 2.2ghz is an inch faster than Palomino @ 1667mhz, they're satisfied. There's no point in upping it too far. As long as they have a flagship that's faster than AMD's flagship, even by an inch, it will sell. They don't care about delivering users super-duper performance, since all they care about is their stockholders.