Differene between 423 and 478?

I have my system sitting here and it currently has an ECS board with a socket 423 1.7GhZ P4 in it. I've upgraded my graphics card to a Ti4600 and am now looking at *maybe* upgrading the board and chip. My question is what kind of performance differences will I notice if I go with a 478 board. Obviously there is a wider range of P4 chips at much higher clocks to choose from, but what would you guys recommend as far as a 478 board and chip. Should I buy now or are there some better things coming out in the next 6 months that are worth waiting for?

Any help is appreciated!

Wel lwith 478 you gan get faster CPUs adn 533FSB over your vcurrent 400fsb. I don't know much else but I would really recomend gonig with the Abit IT7-MAX and a P4 2.26, those are very OCable.