I have a AMD Athlon XP 1700+ in a Jetway 266B with 256MB SDRAM is slower than my Duron 700 with an MSI Motherboard. I am talking here about general use such as internet and word not games whic my athlon xp excels in.
What i am saying and that i have learnt the hard way is that a good motherboard can also make a massive differance to the pc.
Also don't let this put you off athlons my friend has a 1.2gig athlon and its very very fast he runs it on a Abit motherboard.
I hop this helps Michael