I would personally get the 533 because you can get a higher FSB with it.
<font color=blue>I want to save the world for my children, but not my children's children, because children shouldn't be having sex. - Deep Thought</font color=blue>
1.) It doesn't run stable with DDR400
2.) It doesn't run stable with AGP8x
3.) There is a board with the same chipset that has neither of these problems. This would indicate the manufacturer is the problem.
<font color=blue>You're posting in a forum with class. It may be third class, but it's still class!</font color=blue>