For cooling, which is better - open case or sealed case with fans?

Assuming a tower case, which is going to keep all the hardware cooler,
the case open on both sides or a sealed case with a pusher on one end
and a big puller on the other?

Thanks for all input.

On Tue, 7 Apr 2009 16:26:36 -0700 (PDT), muzician21



First I should say it doesn't necessarily matter which is
cooler, only that it is cool enough, at a desirable
compromise of fan noise, dust accumulation (even if it is a
filter cleaning interval), EMI escaping an open case, and
subjecting the parts to potential external stresses with the
case open such as children, pets, spilled drinks, etc. Thus
unless the system is very frequently fiddled with, parts
added or removed for example, keeping the side panels on is
a good goal.

A case with poor design may run cooler with the side panels
off. A case with reasonable design may run some parts
cooler and others warmer with the side panels off. A case
with good design will run some parts significantly cooler
with the side panels on and any that run hotter, do so to a
negligable extent as any part susceptible to overheating
should have heatsinks ample to keep them cool enough in a
properly designed ATX case, closed.

Perhaps a better way to put it would be that different
systems have different issues, one needs look at what the
temperatures are when the case is closed and if they are too
high, what the weak link is that caused the parts to exceed
the desired operationg temp range. Generally speaking if a
case has poor enough airflow that it runs cooler with the
side panels off, a better solution is to add another fan.

Since it can be burdensome to strip an entire system down so
that the parts in it aren't exposed to shards of metal
resulting from cutting a new fan hole, a common solution is
to take off the side panel and put the fan hole in it
instead, situating the fan either across from a particular
part that is running too hot if there is only one, or if the
entire system runs a bit higher than desired then place the
fan in the lower right quadrant of the system (when looking
at the left side) so this intake fan's air flows the
greatest length reasonably possible towards the exhaust
fans, cooling as many parts as possible along the longer air
path.

In other cases this is not necessary, if the front intake
fan is mounted on a grill with ample open area but the
system is still starving for air it tends to be from a front
bezel that lacks ample openings, so the bezel might be
removed and it's open area increased instead of adding a
side panel fan, or by doing both of these things it may
allow lower RPM, quieter fans.

Sealed case with fans. Temperature in case will be warmer, but airflow in
sealed case will keep individual components cooler, and THAT is what you
want. -Dave

A closed case with fans will keep the hardware cooler because air is forced
through the case instead of relying on convection to keep things cool. My main
computer has two exhaust fans and no pusher. I leave the front plastic cover off
to reduce restriction of the air flow. My processor is currently running at 32
deg. C and the motherboard is 29 deg. C.

muzician21 wrote:

--
Mike Walsh

It depends on the design of the case, including fans and interior layout...

Old airplane engines were air-cooled by airflow over the cylinders that
simply stuck out in the breeze. Later, cowls were put over them to reduce
air drag. Some intelligent people discovered that a cowled engine also
stayed cooler, and that evolved into today's closely cowled engines in
almost all piston engine designs. However, those designs must be
deliberately designed to ensure cooling air to all the cylinders.

Likewise, an open case will likely adequately cool a low-power system.
However, in a higher power system, airflow through the case has to be
engineered to cool the motherboard chips ("Northbridge" and "Southbridge"),
graphics processor (GPU), and hard drives as well as the CPU. If you look
in a higher power system these days, you will find large finned heat sinks
on all these components. Good airflow over all these components is crucial,
and may be enhanced by a closed case with well-placed fans.