Here's a reasonably good article you could read. I very much oversimplified it with my previous comment. The Athlon64 works differently again, because it doesn't really use a front side bus in the way earlier chips do. You still use clocks and multipliers with them, but they don't really connect via a front side bus because the memory controller itself is on the chip.

I personally pull that sort of stuff straight out of my head. Writing about IT technology is my line of work


http://www.directron.com/fsbguide.html