Basically there are there types of P4 mobo:
1. S423 pair with RD-RAM for early stage P4 --> FSB400???
2. S478 pair with SD-RAM (older S478 chipset) / DDR-RAM (newer chipset) --> FSB 400/533/800/1066(for extreme edition)
3. LGA775 pair with either DDR or DDR2 -->FSB800/1066(for extreme edition)

This post has been edited by jcliew: Jan 1 2008, 10:14 AM