What will happen if a cpu's fsb is faster than the memory?

Ok now let me clarify. I ignorantly bought a new cpu off of ebay without researching compatibility issues. I'm using a dell dimension 2350 and the memory runs at an fsb of 400mhz (I believe). The new processor has an fsb of 533mhz. I'm really don't know a lot about multipliers and all of that. Will this cause instability? Will it cause the system to run painfully slow. Or will the system pretty much underclock the processor to match the speed of the memory. Just incase it matters; my motherboard is a rev a00 (I cant find much doention on it)