Grex Hardware Conference

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Grex Hardware Item 187: ATX Cases
Entered by ball on Tue Jul 25 06:23:28 UTC 2006:

In ATX and microATX cases, is the power supply fan supposed
to suck air from inside the case (near the microprocessor)
and blow it out of the back, drawing air in through vents
elsewhere in the case (assume there are no additional fans)?

10 responses total.

#1 of 10 by gull on Tue Jul 25 18:16:56 2006:

Yes.  At least in ATX cases that's true; I haven't built a microATX 
system yet.  I don't think I've seen a computer case design where the 
power supply wasn't the exit point.

#2 of 10 by ball on Tue Jul 25 18:51:24 2006:

Thanks gull.  I'm thinking about how to achieve a nice
balanced airflow inside some ATX and mATX cases that I will
be using.  There's a hole for a 60mm fan next to the PSU.
Without a fan there I suppose warm air that's just come out
of the PSU can easily get sucked back in. If I add an exaust
fan there, then I may even get a down-draught in the chimney
and cooler air coming in the side or front of the case.

#3 of 10 by ball on Tue Jul 25 18:56:35 2006:

Who knows, perhaps I'll even get a breeze past the disk
drives!  ;-)

#4 of 10 by gull on Wed Jul 26 05:01:24 2006:

Probably. The idea is to create a slight negative pressure inside the
case, so air is drawn in through the front and side vents.  I've seen
some machines where this was carefully engineered (the IBM PS/2 series,
for example) but in most cases they just throw a couple of good-sized
fans in the back of the case and hope. ;)

#5 of 10 by ball on Wed Jul 26 06:24:06 2006:

I was actually thinking of creating a very slight positive
pressure (assuming I could muster that much control) and put
a simple filter over the intake to reduce the ingress of
dust (bunnies).

#6 of 10 by gull on Thu Jul 27 17:40:25 2006:

I've seen systems that did that by having the sole intake in the front 
panel, and putting a filter on that.  It's common on industrial PCs.

#7 of 10 by ball on Thu Jul 27 23:34:13 2006:

Sounds like I'm barking up the right tree then.

#8 of 10 by arthurp on Sun Oct 1 06:41:13 2006:

If there is a sole intake it can be very difficult to get circulation
past critical items such as disk drives.  Be careful and make a real
effort to have temperature sensors on critical components that you can
monitor and log in software.  At least for the prototype.

#9 of 10 by ball on Sat Apr 2 03:03:52 2016:

    My new PC is built in a SilverStone SG13 mITX case,
which is about the size of a shoe box.  I like that it takes
a standard ATX PSU and a 120mm intake fan. I dislike that my
3.5" hard disk drive must be mounted upside down.

#10 of 10 by ball on Fri Oct 5 20:53:44 2018:

    This week I recycled my 32-bit PC, which was built in an
Antec TX640B tower case.  I have to wait until Tuesday to
recycle my 64-bit test rigs.

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