preferred fan speed control methods?

[Ben Scott]

On 11/29/06, Drew Van Zandt <drew.vanzandt at gmail.com> wrote:
> A comment on Dave's question about fans blowing in vs. out:

  And another:

  The original IBM-PC's power supply fan drew air from inside the case
and then blew it out the back.  Everybody since has done the same
thing.  Humans are great at mindless imitation.  Every now and then
you see a design that has some new thinking, but they're rare.

  I don't know why the original IBM-PC was designed that way, but my
guess would be it was because the PS was, by far, the biggest heat
generator in that system, so it made sense to exhaust the PS outside
the case.

> Higher-pressure air inside also helps keep dust from sneaking in the
> crack, as there's airflow out through even the tiniest ones.

  Yup, positive case pressure with filters on the intakes is the ideal
way to go.  I retrofitted a system to run that way once, and it made a
huge difference in how much dust collected on the innards.  Of course,
it does necessitate regular filter cleanings.  Forget, and the filter
clogs and you loose all airflow.  Then you *really* have a cooling
problem.

-- Ben