What fan should I use and where to put it in my comp?

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I just put in an ATI video card that has a heat sink and fan. However, my
comp also has 3 opticals and 2 hard drives. I think I better put in another
fan. I was thinking about a slot fan, but I do not know what I need to do. I
can't tell if my the fan on my front panel is sucking or blowing, and I
don't want to suck any air off my graphics card by putting in a slot fan.
Can you tell me what I should do?

Here is the fan I was thinking about getting:

Below are some pics of my comp. There are two links for the same pic, so you
probably need to click on just one link.

There are 6 small holes on the plastic cover of the front. But I think these
are mostly for look though.

This is my fan on the inside of the front panel of the computer. I cannot
tell if it sucks or blows.

This is the front panel on the outside. The fan is right on the other side
of these holes.

This is the back panel of my comp. You can see vent holes from top to

This is what the vent holes on the back of the comp look like from the
inside of the comp.

This is another shot of the back panel close up.

Inside shot of my whole comp.

Another inside shot of my comp.

Re: What fan should I use and where to put it in my comp?

On Fri, 9 Dec 2005 22:14:23 -0600, "Wilson"

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This slot exhaust will tend to have higher noise/flow ratio
than a traditional rear-case exhaust fan.  Unfortunately,
your case is horribly designed for modern gear and will not
take an 80mm or larger rear exhaust fan.

Given a will, some sheet metal and a bit of imagination it
could be done but a whole lot of work for a case that still
has issues.  IMO, that is the kind of case that should never
have been made because there is no target system it would
cool properly, even on a slow old system the bottom front
intake fan is only a problem.. but more on that below...

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Yes those holes might as well not be there.

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It blows into the case.  Problem is that with the gaps
around the metal behind that plastic frame-holder, and with
no good front intake, and even further with the stamped in
metal minimalized holes in front of it, what little air it's
moving is going to be drawn through the front bezel from the
top interior of the case, merely recirculating the air.

However some cases like this also have a slot at the bottom
of the bezel, under it... if that's the situation then it's
good to elevate the case off the surface it's on, have an
inch or two of the case hanging out over a suitably size
piece of plywood or something... though I'm not actually
recommending you do this, it would merely help a little bit
if the case were otherwise suitable.

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This is far too restrictive for good flow... ideally you
would cut out a large, 92mm hole the shape of a fan mounting
and secure the fan to this with rubber isolating grommets-
because the case metal is too thin and a fan attached
directly would tend to cause vibration induced noise.

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There's probably a high % of the case's intake, coming in
through those holes... which is unfortunate as they're in
the vicinity of the exahaust, especially as a case is
typically oriented next to a wall, even if a few inches away
from that wall it still increases recirculation.

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We can pretty much ignore the vent holes because to optimize
this case they won't make a big difference either way.

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While it may not make a large difference in cooling, it'd be
good to secure those cables.  Due to the routing of the
ribbon cables it might be useful to have round cables
instead.  The power connector wiring is esthetically
unpleasing but so long as it can't get into a fan (which it
might, hard to tell what would happen of the case were moved
at some point in the future), they're not significant for
cooling purposes.

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Your case is an example of one I wouldn't take for free.
Nothing personal, it's just horrible.  My best advice is to
decide now if you want to strip it down and extensively
modify it (measuring, metal and plastic cutting, etc) or
just buy a new case.

Among the other problems mentioned, the front fan (even IF
it were effective which it isn't) is not pushing the air
through the drive rack except "maybe" to a minimal extent
due to the liklihood that it's recirculating air by pulling
down through the chamber in the front bezel.  This means
your two HDDs stacked so tightly together are getting very
little flow, and there's not a lot you can easily do about
that... I'll make a suggestion below about what can be done,
what I have done on different cases that started out with
more potential but on this particular case I would not do
it, abandoning the case first.

The modifications to get this case into good shape:

-  Cut out a large hole in the front plastic bezel.  It'll
be unsightly then, so perhaps make the hole square and put a
mesh filter panel over it, like this:
I"ve seen some in different colors too, like unanodized
silver or white, blue, green, red... in sizes ranging from
80-120mm and the pic I linked is only an example, I didn't
check on whether they're cheaper or better variety of sizes
or colors elsewhere.

I'd put one of those in a hole cut out of the plastic, in a
size as large as possible (in the area of the plastic before
it starts bending around too much, at least 92mm and maybe
120mm would fit- it need not be the size of the fan behind
it, even better if it's larger than that fan).

-  Take sheet metal and fabricate a new drive rack that sits
behind the area where the current fan mounts, and not use
the top 3.5" rack for anything but a floppy drive.  Put a
92mm pusher fan in front of the rack, and cut that size hole
in the case front (metal) wall and mount with isolating
rubber grommets.  An example of such a case retrofitted with
such a setup,
or even two 92mm fans,

As mentioned this may be overkill for your case or you might
not be inclined or motivated to do metalwork, but you won't
get decent drive cooling with the two drives stacked as-is
in the case, nor after only cutting out a hole for intake
and having a fan not blowing through them.  On other cases
designed without a front fan in front of the rack, the
majority, optimally all, of the passive front intake pulls
the air through the drive rack while on your case what
little the front fan does, decreases any fresh air and only
"might" recirculate a tiny bit.

The significant increase in front intake with hole cut in
the bezel is important with your case because you have
insufficient area to mount rear exahaust fans.  A slot fan
would be a compliment but a noisey one per the flow rate
gained, and with such a restricted intake it will also
reduce exahaust through the power supply.  It would tend to
help cool the video card some, but an added drive rack as
I'd pictured also does a great job of flowing air past a
video card, and yet such a rack can be too deep, careful
measurements are necessary to determine if it will fit as
the rack is deeper than the drives-ends to provide the space
for the fan as well becuase it's mounted on the inside of
the case wall.  If your case's plastic bezel is thick enough
it might be possible to mount the fan on the outside of the
case wall instead, within the plastic bezel cavity, though
it might then be very close to a front filter as I suggested
above and thus you might not get effective flow though the
entire filter panel, only through a portion butted-up againt
the fan housing.  Further if this panel is too close to the
fan, it could be flexed backwards and contact the fan blades
unless there's also a (tubular) grill mounted on the front
of the fan.  Such a grill could instead be mounted on a
carefully cut hole in the front plastic instead of a mesh
filter but overall I think it's a less polished look and the
filter also does the obvious- filters the air too.

So in the back there isn't a lot of option for exahaust- you
could probably fit a pair of 60mm fans after cutting out
holes for them but 60mm has such a poor flow to noise ratio,
and poor flow to cost ratio as well.  IF you did mount rear
60mm fans choose 25mm thick rather than any thinner.

A large fan mounted into a cutout in the side panel would
help cool the video card if mounted low enough (oriented as
an intake, blowing into the case).  This won't help the hard
drives much if any... a second fan might be positioned up
near the drive rack but it will push only a limited amount
through the drives due to the rack design and close mounting
of the drives... certainly not optimal and probably not
worth the effort.  Then again, IMO the whole case isn't
worth the effort but there are a ton of old cases with this
type of poor design so I only do the writeup if someone is
desperate to reuse on, wants some modification practice, or
wants to reduce adding to landfills by reusing what they
have instead of replacing one.

Otherwise if it wasn't clear already, all this modification
will require removing all the parts, a lot of measuring,
cutting, cleaning out metal fragments, and then reassembly.
If you had the inclination to do it, there might still be
reason to buy another case and just mod this one for some
other use in the future... or even NOT modifying it, only
using it for something at which it's more suited.

For example, if you unplugged the bottom fan, put an old
board and CPU (or drastically underclocked modern combo),
put only one optical drive (or none) and mounted a couple
hard drives in the upper two 5.25" racks rather than in the
3.5" racks, by leaving the 5.25" slot covers off the PSU
would draw a large % of  intake through these slots, cooling
the drives.  Place a piece of filter material over the
opening and you have a relatively quiet filtered intake for
the drives... the key being that the lower half of the case
has nothing particularly hot running (video or CPU) so
there's no need to add more flow to the bottom of the case.
Result is a quiet fileserver with the only work to the case
being (not using) bottom fan and cutting a filter for the
open top bay(s).  Attachment of such a filter depends on the
thickness of the medium, thick material like used in furnace
filters might stay in place without additional support but a
thinner filter might have adhesive-backed foam added, like
back weatherstripping foam commonly sold at hardware or some
automotive stores.

For a primary use system, I'd get a different case then with
that one empty you can decide if you want to do anything to
it or not.  The other lazy option is the brute-force method,
just take the side panel and put a couple of low RPM
120x38mm fans in it, further undervolted to reduce noise,
blowing into the case.  You'll probably want fan guards on
those as well.  These two large fans will push so much air
that it's going to be forced out every nook and cranny, so
unplug the bottom front fan as it's only working against the
two new fans, air will be flowing OUT the front, as well as
out the back and anywhere else.  

You'll also have to take great care in securing any and all
cables if you did this, they'd be touching the cables as
they're pictured in your case at present.  Generally not the
best option, just the easiest as you don't even have to
disassemble the system components, just taking off the side
panel and cutting a couple of 120mm diameter holes.  Even
larger single fan would have a similar effect but it gets
harder to undervolt larger fans to reduce RPM enough that
the noise is reasonable.  For the two 120mm (or any other
case fans for that matter) I suggest Panaflo "L" (low) speed
in whichever size is warranted.

Re: What fan should I use and where to put it in my comp?

Just to update you guys. I separated the hard drives, I moved the pci card
over one slot, I opened one of the 3.5" bays on my front panel, and I put in
those fancy rounded cables in place of the ribbon cables, and the computer
is about 3 inches off the carpet.

I now have a gaping 3.5" hole on the front panel though where the floppy
used to be. Wonder if that is even necessary? Also, it seems like this would
work against the fan on the PSU. I would think the front panel fan is to
bring in new air, push it to the back, and along with the PSU fan both
should try to push the air out the back of the comp, where I have alot of
little vents.

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Re: What fan should I use and where to put it in my comp?

On Sat, 10 Dec 2005 14:24:11 -0600, "Wilson"

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Does it have any air intake under the bezel?  If not, most
of the intake is going to be through that newly opened bay,
which will help the immediately adjacent HDD some, but does
nothing for the video card on the bottom.  If this is how
you  are going to leave it, I would add that slot-fan you
linked earlier, though "I" would still try to increase the
intake area more.

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That what, floppy?  Leave it in, what good is a drive
sitting on a shelf?  If you're really desperate to not
modify the case, I suppose it would be easiest to remove the
floppy, leave the case cover off on the space in the middle
rack position and have one drive above this empty position
and the other drive below it so the intake flows between

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How so?  Any and all passive intake is a benefit for
purposes of the PSU fan exhaust.  The issue is where the
intake is to the extent of what areas it flows across, that
by having this opening mid-case, you have created more of a
dead zone in the lower half of the case.

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The ideal and original purpose of a bottom front fan IS to
draw in new air.  Problem is, (to put it bluntly) they
screwed it up royally.  For that concept to work well the
fan has to have at least a moderately unobstructed intake
area to the exterior (room air) and a fairly enclosed
(partitioned off) area between the fan intake and the
unobstructed external intake.  In other words, a channel
effect so air is fairly forced to flow in a beneficial way,
and minimal impedance against that.

In other words, if you were to cut out an 80mm hole and
mount the fan directly to the front metal wall of the case
and not have the plastic front bezel on it (this is just a
hypothetical since the bezel is so restrictive), the fan
could be expected to move multiple times as much air.
Ironically enough, the PSU would have better exahaust if the
front fan wasn't there and there was a big hole, than with
the front fan and nothing but those tiny holes.

What usually ends up happening (on any decent modern PSU
with a thermally controlled fan) is this restriction to flow
heats up the PSU, then the PSU fan speeds up to compensate,
so you have both more noise and hotter PSU.

Re: What fan should I use and where to put it in my comp?

Thanks for the assist Kony.

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