# airflow inside my case

J

#### John Doe

So I put together another computer and opened my main computer case
recently. It's been way too long. I reversed the rear exhaust fan up
near the power supply and put a filter on it so that it (in addition
to the lower front intake fan blowing on the hard drive rack) would
provide positive air pressure inside of the case instead of risking
negative air pressure that would work against the power supply fan.
A reasonable person might consider that theory debatable, but in my
opinion it's not worth risking negative air pressure causing minimal
cooling of the power supply. Since there probably was too much
positive air pressure inside of the case, I just popped open two
metal cut-outs on the back of the case to release some of the
pressure and provide greater airflow through the case. Come to think
of it, why not have somewhere approaching twice the airflow than you
have with one intake and one exhaust fan and both fans blowing cool
air into the case simply by making a passive hole that equalizes the
air pressure at the same time?

Good luck and have fun.

A

#### Andy

So I put together another computer and opened my main computer case
recently. It's been way too long. I reversed the rear exhaust fan up
near the power supply and put a filter on it so that it (in addition
to the lower front intake fan blowing on the hard drive rack) would
provide positive air pressure inside of the case instead of risking
negative air pressure that would work against the power supply fan.
A reasonable person might consider that theory debatable, but in my
opinion it's not worth risking negative air pressure causing minimal
cooling of the power supply. Since there probably was too much
positive air pressure inside of the case, I just popped open two
metal cut-outs on the back of the case to release some of the
pressure and provide greater airflow through the case. Come to think
of it, why not have somewhere approaching twice the airflow than you
have with one intake and one exhaust fan and both fans blowing cool
air into the case simply by making a passive hole that equalizes the
air pressure at the same time?

Good luck and have fun.

You should perform termperature measurements to prove your theory. My
experience has shown that using a fan to push cold air into the case
is less effective in cooling the air inside of the case than using a
fan to exhaust warm air out of the case while allowing cool air to
enter the case through various openings in the case.

J

#### John Doe

You should perform termperature measurements to prove your theory.

Which theory? Do you think it's okay to put negative air pressure on
My experience has shown that using a fan to push cold air into the
case is less effective in cooling the air inside of the case than
using a fan to exhaust warm air out of the case while allowing
cool air to enter the case through various openings in the case.

Have you also argued for reversing a CPU fan?

Are you trying to say that air being pulled is cooler than air being
pushed? I don't need temperature measurements (real or imaginary) to
understand the outcome of that theory.

You don't want dusty air coming through your CD drive and over other
components. If you have intake fans, you can filter the air coming

G

#### geoff

With my old case, I had one 80 mm fan in the front bottom, sucking air in
and 2x80 mm fans at the top sucking air out.

The PS has one rear and one top fan sucking air out.

With that case, the MB was about 32c most of the time. After I got my P180
case, same MB but hotter processor, the MB temp stayed around 25c. The P180
has several 120mm fans.

-g

J

John Doe said:
Which theory? Do you think it's okay to put negative air pressure on

Have you also argued for reversing a CPU fan?

Are you trying to say that air being pulled is cooler than air being
pushed? I don't need temperature measurements (real or imaginary) to
understand the outcome of that theory.

then this whole thing is just rhetoric