The boys at System Cooling have a article on overclocking. Pretty neat, check
out what they have to say here.
The other day I was sitting around with nothing better to do, so I decided
to put together a system out of some of the unused parts sitting around the
test lab to use as a cruncher for the Seti@home DC project. As it was going
together, it occurred to me that for all the overclocking going on in the lab,
and all the tinkering I'd done, on literally dozens of machines, I had never
once done a full comparison of the overclocking potential of a completely stock
cooling system versus the premium cooling that equipped most of the lab machines.
As a matter of fact, I couldn't recall ever doing ANY overclocking of any of
the systems with the stock cooling in place. Since I had all the components
right in front me, I decided to do just such a comparison.