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Re: CPU Cooler designs?

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A nibbler.

A nibbler would be better there too, bigger bits of metal.

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Yep, even the wilds of that soggy little island.


Re: CPU Cooler designs?

On Fri, 29 Sep 2006 17:47:18 GMT, Tom Goodman

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It's not quite that simple, particularly with stamped-out
metal holes because they increase turbulence, reduce flow
rate more than you'd otherwise have per diameter of opening.

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Yes, what you have done is very desirable for reducing heat
in poorly designed cases or improving flow:noise ratio in
any case, unless you're an OEM with EM emissions to combat.

Removing those stamped holes also decreases dust buildup
that further blows exhaust and intake, and allows lower fan
RPM which increases the fan lifespan.

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I have no idea if it can be bought in London, I presume
"somebody" carries them- try a metal supply shop, for trades
like HVAC (you might call a larger local HVAC company and
ask them- many may have ongoing relationships with such
suppliers).  There's probably someplace on the internet as
well, but never having looking for one in London...

Hand nibblers are good for 0.6mm, maybe 0.8mm sheeting.
They aren't so good at making nearly perfect rounded holes,
they snip off a few millimeters at a time in a straight
line.  You can try to rotate the tool while cutting with
limited success, but it's not going to be a finished look if
the metal isn't pretty thin- if you've worked with hand
tools a lot and have very strong hands and forearms, you can
muscle it into curving more as it cuts but it's not the
ideal tool for the job on anything but straight cuts- though
it doesn't leave tiny metal shavings everywhere, does have
that going for it.

There are electric nibblers or shears too (the former better
for tight areas, the latter better for steel over 1mm
thick), in a wide variety of prices depending on the quality
of the tool.  Often over $200 USD.  Seldom do I hear of
anyone using one for casework, but if you did a lot of it
and cut out rectangular holes it might be useful.  

If the case is small, and 0.8mm or otherwise 1.0mm or more
and the case is fairly well designed (sufficient folds and
bracing such that it doesn't vibrate as much) I find an
(electric) sabre saw better at the task, and of course
drilling the starter holes where necessary.  Using a very
fine toothed blade is important, otherwise you may end up
with ripples in the metal.

Some people prefer to use a hole saw, but since the fan
housings flare out I prefer to cut a near square hole with
sloping corners around the mounting holes.  It can help to
rip around a cheap fan in the sizes you use and use it's
frame as a template for marking out the case.  Masking tape
along the sides of the cuts help to preserve the case finish
with the sabre saw or other tools which glide along the
surface while cutting.

Metal particle removal must be thorough, some cases can be
washed out but others it would take so much time to remove
pieces that a good old paint brush and strong magnet get
enough off and I've never had a problem with that method
either.  Most often I don't cut out the newer cases though,
I prefer the older ones as they more often had thicker metal
and without holes everywhere you can better control where
your intake and exhaust is, and have a better looking result
if your fan hole is in a solid paneled area rather than in
the middle of, interrupting a bunch of stamped holes.  For
example, some of the old HP cases stamped out fairly odd
shaped patterns on the rear and used a 92mm fan, but the
holes extend further than the fan frame (were only blocked
by HP's inclusion of a plastic duct/snorkel assembly that
extended down towards the CPU 'sink).

Re: CPU Cooler designs?

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I use aviation tin snips
<http://www.mrtool.com/browse.cfm/4,756.html .

Re: CPU Cooler designs?

"Tom Goodman" wrote:
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    I also found flow rate greatly increased after removing the
    the grills over both the case and power supply exhaust fans.

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    I was also leary of metal particles, so I used an electrician's cable
    snip.  The punched metal grills over the exhaust fans are pretty soft,
    so the snips will bite right through them, and I didn't have to use any
    plastic or other kind of sheeting to catch any metal bits.

    If you want to experiment with increasing laminar flow at the exit,
    try using putty or modeling clay to smooth the step between the fan
    venturi and the case lip.  My guess is that it will decrease the
    "whoosh" sound noticeably, and it might increase the flow rate
    by not having the air "trip" as it exits the case.


Re: CPU Cooler designs?


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So  what ??

That's exactly the way it is in conjunction with my rear case fan and
vented front-panel with my Zalman9500 @ 1600RPM on my X2 4400+
( o/c'd to 2.6GHz, absolute max.  case temp 48 degrees C). Cools the
memory very effectively as well.  The Zalman design is quite brilliant
for its efficiency and smart airflow pattern while still only slightly
over the CPU manufacturer's max. recommended heatsink weight. Which
is no worry on my A8N32-SLI with the provided board-stiffener
in the CPU area.

I am not familiar with the Dell hardware you describe ?  BTX-style by
any chance ? In which case a high-performance video card will nicely
bake in the exhaust air from the CPU and memory area. Not surprising
in a totally CPU-centric motherboard design from the same wizards that
brought you the hand and foot-warmer called the P4-Prescott.

John Lewis

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Re: CPU Cooler designs?

Gerry_uk wrote:
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darn right!!! but no how you think.

The fans have been installed backwards!!!!!!

The (CASE FAN) fan above the CPU is an exhaust fan. It blows the hot
air out of the computer.

There is also an intake fan on the front at the bottom. Usually hidden
"thanks" to the cases with snazzy fronts and some tiny hole somewhere
stopping you seeing how it can get any air in. But if you open the
computer you'll see a space there to fit a fan.

this also makes sense because hot air rises.

I'm sure I once saw a picture in a document called  AMD cooling
requiremetns or something, that showed an arrow indicating the
directino of the air. Anyhow, it is like that.

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Interesting point. I think I saw in a scott mueller video that CPU
heatsinks do **Suck** air downwards and blow it out the bottom.  I
almost forgot about that.
Where did  you read that?

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the front of the case is nowhere near the CPU.  And generally the fan
is at the bottom front.

The CPU is at the back of the case near the top, just below the PSU.
It's impossible for a front fan to suck air in over the CPU.  It's far
away. It just sucks air into the case.
Unless this server is somehow unlike any computer i've ever seen. But
if it uses an ATX MBRD then I find that hard to contemplate.  You
should have included a picture - if you could find one.

Re: CPU Cooler designs?

Hi q_q_anonymous,

Scroll down...

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No, I'm not talking about the intake fan or outtake fan, I'm talking
about the CPU fan, the one that is part of the CPU cooler. As I
understand it, this fan blows DOWNWARDS onto the CPU.

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I thought it was common knowledge, but wanted clarification.

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The Dell machines don't use ATX. You are right that not everyone on this
group is familiar with the Dell business line of machines so it was
probably a bad example. You can however, see pictures of the models I
listed on the Dell site.

The way they have done it is to have a desktop case, with the CPU right
at the front of the mainboard. The air is taken in the front of the
case, straight over the CPU and ducted out the back. It's very cool and
very quiet even with Pentium D's and Pentium 4s at high Ghz. Note that
I'm not talking about Dell home PCs here, only the business PCs.

The Dell servers are similar in their use of ducting, but the fans are huge.


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