the ideal case layout

[skimzzz]

I can believe how many poorly designed cases are out there. After experimenting, here is what I would consider the ideal case setup for cooling purposes.

-- Tower case, with enermax type PS (92 mm fan intake at bottom free from wires, and 80 mm outtake) at the very top.
-- Slot for 2 80 mm fans 1 inch from the intake at the bottom front (with enlarged intake holes, the size of the fans themselves). Most intake fans are strapped to the case where a bunch of tiny holes are. This reduces air inflow and raises noise levels.
-- a slot for a 80 mm fan in front of the 3.5 inch bays where the HD will sit (also serves as another intake fan).
-- A 120 mm exhaust fan (or 2 80 mm fans) outlet beneath the power supply (a cut out with a grill, not just one of those circular hole patterns).
-- Fan air flow out should be slightly larger than fan air flow in (positive pressure is bs).
-- NO OTHER holes in the case (why do so many cases have all those irratating holes at the back which only cause air flow short circuits?)

Any one have other ideas?

 

[camieabz]

and 80 mm outtake) at the very top.

Heh. I thought an out-take was usually seen in the credits of a Burt Reynolds film. I think 'exhaust' is the preferred word. Back to the point.

Seems like a lot of slots. Remember to try to keep a good continuous airflow.

positive pressure is bs

Hmmm. Why?

Positive pressure prevents all the little cracks and holes from sucking in dust.

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[HonestJhon]

and puts more air molecules in the case, to flow across the surface of the heatsink.

-DAvid

-Live, Learn, then build your own computer!-

 

[skimzzz]

with case fans, pos pressure would decrease the flow of air and therefore, you would have less air molecules flowing across the components (plus the air moecules would be warmer).

 

[Guest]

The increase in pressure would raise the temperature of the air by a slight fraction of a degree, you'd have a hard time finding an instrument that would read the change. The point of positive airflow is, for the most part, to control dust by filtering the intake and in a case with that much air flowing through it dust becaomes a problem. You probobly wouldn't see much, if any, difference in cooling.

Increasing pressure wouldn't decrease airflow; in fact, negative pressure would decrease the volume of air flowing through the case, especially if there isn't enough free intake. Positive pressure doesn't mean pumping twice as much air in than out, it means to pump just enough excess air in to keep air flowing in just from the fans, not from every unsealed crack (and let's face it, you are likely to never seal every crack).

 

[HonestJhon]

well, if you have drives that are accessable from the outside of the case, then no, you will never seal all the cracks.
but dude, i dont know how much that increase in temp is going to matter, if you think about it, since the case is not sealed, then it wont build up enough pressure to make a temp change that is noticeable...
of course, the optimal would be to have the same ammount coming in as going out, but to do that, you would have to actually measure the intake and outflow of air. and then adjust the fans to the point that they are equal. and use adjusters that are to a high tolerance (which means high expense) so that the fan speed is a constant, which would make the air flow the same. most of us dont have the equipment, or resources to get it that good, so what i usually tell people to do is to have a little more pressure in there. that way, they wont really worry about dust as much, if they filter it of course.
and i personally have had problems when i have negative pressure in the case...
and i ahve never been able to get it even, because there was always something going wrong, either i didnt have two exactly same fans, or something was restricting the air flow somewhere...



-DAvid

-Live, Learn, then build your own computer!-

 

[skimzzz]

Dust will still get into the case with pos pressure from where the intake fans blow in. Only not as much since the air flow is decreased due to the pos pressure. If you are so worried about dust, why don't you turn off all your case fans?

I am also assuming you don't have one of those cases with a million stupid holes in the back panel. In that case, pos pressure would be good.

 

[Guest]

That is why you filter the intake.

 

[HonestJhon]

dude, if you filter the intake, and have some exhaust, then you will have little to no dust, and good airflow...
but when filtering the intake, you have to take the fact that a filter restricts the airflow, so the intake has to be a little bit more than the exhaust..
and dude, skimzz, you cant tell me that you would rather not have to open up your case to clean the whole thing when it fills up with dust....and turning off the fans is dumb, seeing as how that would defeat the purpose of having the fan....
come on....dust is just a nuisance, and an easy one to get rid of...filter the intakes...and close up the holes that are on the case...like those predrilled ones that they put so that you can mount an 80mm fan...just cover them with some duct tape or something...that is what that stuff is for anyways...ducting air, and this is what you are trying to do when you control the airflow in your case.

-DAvid

-Live, Learn, then build your own computer!-

 

[HonestJhon]

SHLA-ZAM!

-DAvid

-Live, Learn, then build your own computer!-

 

[camieabz]

Yep. I use dust filters on my intakes too!

Hope Crash doesn't see this one. Anti dust RULES!

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[HonestJhon]

well, right now i dont have it filtered...i wan to get something that will not really constrict the airflow, but filter it pretty good...and be cleanable, or easy, and cheap to replace.
been trying a few materials, and when i figure out which is pretty good, i will let you guys know.
experimentation...SHLA-ZAM!

-DAvid

-Live, Learn, then build your own computer!-

 

[OldBear]

I don't know how you could get them but panty hose work well.

<font color=blue>Remember.... You get what you pay for. All advice here is free.</font color=blue>

 

[HonestJhon]

AHYUK, i'll just take them frum the wash!
i sees lots of em floatin by when i be huntin 'coons..
damn, this hick thing is getting out of control...lol

but i will try that..
get one of my lady friends to buy me a pair....not for me...for my computer...lol


-DAvid

-Live, Learn, then build your own computer!-

 

[bw37]

skimzzz,

Positive pressure and filtering the intake air is undoubtedly the best way to go if you can do it. Dust is more than just a nuisance, it's also a great insulator: the LAST thing you want coating your HSF and other heat dissipating devices like HD's, etc.

It probably doesn't help the efficiencies of the fans either. I'm always surprized how quickly it accumulates. It's also a pain to get rid of without risking zapping things with static (vacuum cleaners a good static source) or blowing the dust into the bearings of a fan or floppy drive (been there done that). So in my opinion, keeping the dust out is the best solution. I wish the case builders would do this right. It would be so easy to add a large area filter just inside the front air intakes.

my $.02

BW

 

[skimzzz]

I guess I dont put dust that high on my list of nuisances. I'd rather set up max air flow. Before i tinkered with computers, I had a dell whose case I opened after 2 years. The system was caked in dust. i just blew it off and it was no big deal.

You can actually make filters easily. At places like home depot, they sell all kinds of filter materials for heating/ac/air filters. For the price of one case fan filter, you can buy a whole slab to custom cut which will last you forever.

 

[bw37]

Yeah, I know. I've done it using some rain gutter covering (aluminum expanded metal) and some 3M Filtrete AC filter material. Works OK, but the case design just makes it harder than it needs to be to really force all the intake air to go through the filter.

BTW, I've got a couple old systems that worked OK caked w/ dust as well. The only case fans they had were in the PS so they didn't exchange anywhere near the CFM of air (and dust) that current systems do. They weren't exactly high performance, high wattage, that I was trying to O/C to the max. When max. O/C is your goal, every little bit helps I should think.

Besides, I just like to work on a clean machine!

BW

 

[Guest]

Nothing worse than finding out you have to evict a family of dust bunnies when you open up your case.

 

[cprfan]

I can believe how many poorly designed cases are out there. After experimenting, here is what I would consider the ideal case setup for cooling purposes.

I can just imagine with 6-7 fans how loud a system setup this way would be.

-- Slot for 2 80 mm fans 1 inch from the intake at the bottom front (with enlarged intake holes, the size of the fans themselves). Most intake fans are strapped to the case where a bunch of tiny holes are. This reduces air inflow and raises noise levels.

I know of no case that does this, but the best location for an intake and pair of 80 mm fans is on the bottom of the case blowing air straight up through the case and out.

-- A 120 mm exhaust fan (or 2 80 mm fans) outlet beneath the power supply (a cut out with a grill, not just one of those circular hole patterns).

Why not duct the heat from the CPU/HSF through a duct or shroud to the outside of the case instead of swirling the generated heat with fans all around inside the case ?.

-- Fan air flow out should be slightly larger than fan air flow in (positive pressure is bs).

NO ! NO ! NO !, a industrial "makeair" system works by slightly pressuring the building, blowing out dust through cracks and such, the same can be said of a computer system setup the same way.

 

[HonestJhon]

that duct trick is what manufacturers like dell and gateway use to keep their systems running in the green. i want to make one for my computer, or take one out of a dell...hehe
but the thing is, i would want to reverse the direction of my heatsink's fan so that it sucks cooler air in from the case, and out the duct wouldnt i?

-DAvid

-Live, Learn, then build your own computer!-

 

[Guest]

Why not just make a sealed (filtered) duct, basically a tube, to pull air from outside the case to your heatsink fan, then use a plastic duct or a trategically placed exhaust fan to suck the heat right out of your case? Might be a fun project.

In my case I recycled an old Gateway plastic duct to pull all the heat away from my processor, but I didn't pull air from the outside (hot air isn't blown across the heatsink because all hot air is blown out of the case).

 

[Guest]

If i had a duct i would have it suck air away from the proseccor,,,, because you alwasy have a hsf that blows air aways so why not continue the air flow?

 

[HonestJhon]

so basically isolate the heatsink from the rest of the system?

-DAvid

-Live, Learn, then build your own computer!-

 

[cprfan]

that duct trick is what manufacturers like dell and gateway use to keep their systems running in the green. i want to make one for my computer, or take one out of a dell...hehe

I saw such a system, a Compaq I think, that had a CPU duct in a magazine.

Pay a visit to a hobby shop and pick up some sheets of sheet styrene plastic to make such a device.

but the thing is, i would want to reverse the direction of my heatsink's fan so that it sucks cooler air in from the case, and out the duct wouldnt i?

yes sir !