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Push+Pull or Push+Push Dual Fans on Heat Sink

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July 9, 2009 5:54:49 AM

Anyone experimented with Push+Pull vs. Push+Push Dual Fans on a Heat Sink?

I know that Push Push give higher air pressure thus denser air (compressed) and that absorb heat more readily, However, depending on sink dims it also may give slower air speed which tends to negates the gains. On push push if your sink is close to cubed shape then the intake and exhaust area will be the same and it seems to that this is where a push push is better, yes push pull will still have somewhat faster air speed but very little but it seems to me that the better heat dissipation of the denser air will out rank the speed? This is all my crazy little head flatulating.


If I had a sink that is 120 X 120 X 60 then with push push the exhaust area will be half of what the intake area, is this where one should choose a Push pull set up? What do the experimenting prove?
a c 86 K Overclocking
July 9, 2009 6:19:16 AM

Push/Pull increases the total air flow over the fins. It increases the total CFM of air. The air is cooler than the fins, thus you have more cooling.

You cannot even think your compressing the air in an open channel. Also, when you compress air (not applicable in this situation) your increasing the temp of the air.

So your over-flatuating, your unable to compresse air with fans in the first place, anything at all.
a c 197 K Overclocking
July 9, 2009 6:31:24 AM

All you are doing with push-push is having two fans fight each other. Don't believe us. You set up the experiment.
Related resources
a c 86 K Overclocking
July 9, 2009 6:36:28 AM

OMG, push push means no air flow, I completely missed that point. Hahaha!
July 9, 2009 7:52:16 AM

co⋅nun⋅drum
  /kəˈnʌndrəm/ Show Spelled Pronunciation [kuh-nuhn-druhm] Show IPA
Use conundrum in a Sentence
–noun
1. a riddle, the answer to which involves a pun or play on words, as What is black and white and read all over? A newspaper.
2. anything that puzzles.

Here's a a Riddle for you num drum:)  "What compresses air on one side and causes a vacuum on the other side and it has blades that spins? Clue, it starts with "F" and ends with "AN"? Next time you watch the news pay attention to the word "Pressure" and see how it relates to air temperature. Also think of just how much pressure difference they are talking about. You cannot live without compressed air also contrarily to popular opinion air pressure is alway varying, when you feel wind that is a sign of varying air pressure.

Most sink have six side two of which air cannot flow through so if you have a fan on two sides in a push push configuration that still leaves two sides for air to flow out of and the point is to have them "Fight Each Other" to a point to raise pressure but remember, there is still two side for air to flow out of. Now pay attention next time before you blow sNOT all over someones post.
July 9, 2009 8:12:29 AM

(grabs popcorn)
July 9, 2009 4:02:37 PM

HI,
Some review test both setup push-push ans push-pull, it 's seem to be more effective in push-pull. Here is a link to one http://www.dragonsteelmods.com/index.php?option=com_con....

In my setup I have noctua (NH-U12P) 2 fans in push-pull mode . The air flow direction I have his the following one.

a) air come from the top bye 2 noctua NF-P12 , 1 fan's blow on the memory stick the other directly on the heatsink, so the air have lower temps then ambient temps at least 1-2 c.

b) the air is suck and push thru the fins

c) the air little warmer is pull from fins and push on the back of the video card and it's still really low in temp. 27-28c.

d) on th side door I have 2 sctyhe s-flex 120mm to pull everything out of the case.

After testing a lot, is the best solution I can find for my setup, as you know the tj-09 need improvent in air flow departement.

In summer time this setup is more effective because the ambient temp is higher, and the difference forn the first fans his 3-4 cooler inside the case.
I take my temp reading with temp sensor connect to my fans controller. It's not a scientific test but for me that's do the job and give me measures pretty close to the reality.
July 9, 2009 4:49:48 PM

Not the experiment I had in mind, I want to see a test of the same cooler with both configurations preferably with a cooler with equal area. This isn't serious just thinking. You see, I am trying to distract myself from the fact that the UPS truck has gotten stuck in a time sink hole with my I7 stuff but if I can extrapolate the verteron exovector I can warp it here with an Chronometric particle emittor calibrated with dual ion charged crapodium stabilizing units. Yaunderstanswadimtalkingbout?
a b K Overclocking
July 9, 2009 5:30:02 PM

I doubt the push/push configuration would be any good, not only does the airflow would be reduced, but if I remember correctly as any gas is compress, it releases heat and absorbs heat as it expands. Therefore the fans would push air together and as it compresses it would release heat into the heat sink.

By doing the opposite (pull/pull) you might do the opposite and as a finite amount of air is being taken in the heatsink to be pushed-out by the 2 fans, it might expand and absorb more heat.

Both those solutions however don't take into account the fan's performance under various air pressures or the impact on global casing air flow. If the setup creates a heat build-up inside the case, THAT might also negate or worsen any benefit. By having a push/pull setup, you can probably direct the hot air straight into the exhaust fan.

Never did the tests, this is mostly theoretical.
a c 86 K Overclocking
July 10, 2009 7:44:25 AM

LOL, too funny.

I love the funnish noobishness of Toms Hardware new folks.

Glad I have a place to talk to peeps within the realms of reality.

Many start here, fail and just buy a Mac, or fade away. I like fade in these cases.
a c 324 K Overclocking
July 10, 2009 3:34:40 PM

This bruhthakuga guy gets pretty annoying. He wants help, but complains every time someone disagrees with him.
October 27, 2009 11:20:29 PM

In my research I have come to know it is called Positive Air Pressure and it is usefull
a c 86 K Overclocking
October 28, 2009 12:07:28 AM

Okay, what are your research findings? Have you tried your fan experiment yet?

I can Google that too btw.
a b K Overclocking
October 28, 2009 3:02:02 AM

The only definitive testing I have seen is a comparison of one fan and two fans in a push pull configuration. The results were not exactly encouraging. There wasn't much of a temperature drop with two fans. A lot depends of configuration. There are a lot of other factors to consider.
a b K Overclocking
October 28, 2009 6:44:03 PM

I'm reading this with much interest, but there is one thing I wanted to add. I haven't done much testing but I did find two fans pointing the same direction did not make a big difference in air flow.

I have a CPU fan blowing directly on to a system exhaust fan. If I turn off the system exhaust, I don't notice any difference in the air flow exiting the system. I ended up just leaving the exhaust fan off (I have 3 exhausts to vent other air, this one has the HSF right up its ass). This reduced noise and didn't impact temperatures (maybe 1C at best, I didn't see any changes).

Just wanted to add my experience, take from it what you will. I'm not sure if that's even remotely useful, but posted it anywho.
a c 86 K Overclocking
October 28, 2009 8:44:53 PM

Best way to look at this.

If your CPU cooler is pretty much maxxed out due to heatload from the CPU you can do a few things.

First clean up your case air flow. Remove the cheese grate from the back fan. Wire management. Reduce the case inside air temps basically.

Next is to increase the air flow over the CPU heatsinks. Air molecules heat up when in contact with the HS. Once heated up they won't absorb any more heat. By increasing the sirflow you increase the molecules.

It does work. Not all heatsinks can take two fans, not all heatsinks are worthy of such effort.

It's been proven that HIGH QUALITY heatsinks that are near their thermal load capability show a decrease in a PUSH-PULL arraingement.

You better have a place for all that hot air to go. Imagine a PUSH/PULL on a hot i7 in a case with a front/rear 80mm fan. Will you see much gain? No, you silly wabbit!

SpidersWeb, thats not what we are talking about BTW. Your not push pulling on the CPU cooler. Thanks for the info, you have a decent case I suppose.
October 28, 2009 9:59:46 PM

I'm going to have to agree with conumdrum on this one. What he says just makes simple plain sense.

Also, the fact that you are arguing that the push push creates a higher pressure, is just funny, yeah maybe a slight increase, but then you went and contradicted yourself saying that their are still two exit points for which the air to go out of. And since there is an open point the air pressure will dissipate and go to equilibrium before the fans can really create a big difference in air pressure (which like Zenthar pointed out, could be a bad thing depending on your case temps).


Another good solution would be to do just one good high airflow fan.
December 17, 2009 8:36:47 AM

Just wanted to comment,

Push Push would create a higher pressure. Fans create pressure differences. Pressure is the reason fans work. The dynamics of the blades are quite fascinating. You guys seem to be looking at pressure as the pressures you are used to as in a balloon or air compressor, but you must realize pressure differentiations are all around you. Arguing the heat effects from expansion and compression are questionable as the heat release from the changes in such a mild pressure difference are minimal. The idea of denser air allowing more heat transfer is interesting.

He did mention that air does escape via the other parts in the case, this does not mean that compression in the sense of a higher pressure in the case cannot be maintained. The fans act to increase pressure while the escaping air leeches pressure. The leech in pressure will not be in equilibrium in a closed environment with the increase in pressure until a certain compression\pressure in the case is reached i.e. the equilibrium pressure - this is not going to be at the surrounding environments pressure. I might come back later with some thermodynamics.
a b K Overclocking
December 17, 2009 4:34:47 PM

Won't work, if you point them both at each other it will cancel the flow out. PC fans are not very efficient fans really. Put your had over one and see what happens. The flow will stop or reverse out the back of the fan.

Just blowing air on something doesn't always work, you need flow as well. It needs to have a way to get rid of the air.

Its pretty easy to check, just use a cooler with two fan and reverse one and see what happens. I have tested it with fans on opposite sides of a case blowing at each other it canceled out, I can't imagine having them a few inches from each other will work better.

Why you would ask a question then argue with the answer and insult the guy is beyond me? Conundrum has probably forgotten more about computer cooling than you know.

Lets put it this way, if Push+Push worked you would see coolers sold in this configuration. I haven't seen any, or ever seen it suggested. That leads me to believe at some point some guy in R&D has tested it and it didn't work.

I may just have to test it for the hell of it and see what happens.

Paul
December 17, 2009 6:46:00 PM

Anytime you have two fans pushing into a case weather they be just next to each other or one on the front and one on the side they are Push Push, oh yea! So obviously push push works. Pressure presses in omni direction regardless of the direction of flow which is different. In a PC case you get better cooling if you have more fans pushing than pulling air out, hence, Positive Air Pressure. That's Case Cooling 101, my thought that started this discus. . . mud slinging, spree is that with a CPU cooler that DOES NOT have covers that prevent air from blowing out the side, some dont, could increase the air pressure from push push help cooling as with a case.
a b K Overclocking
December 19, 2009 3:32:09 PM

"In a PC case you get better cooling if you have more fans pushing than pulling air out, hence, Positive Air Pressure."

Really? Never seen this to be true myself. Everything I have tried and read you get better cooling with negative pressure systems. Positive pressure systems in my opinion is just wasting cfm and creating turbulence in the case. I have not seen one test where positive pressure increased the cooling inside a case. Please link me to some data that says otherwise and I would be more than happy to read it.

Paul
December 19, 2009 5:00:03 PM

Negative air pressure causes jet a stream where the air will take the shortest distance from the the pushing fan to the pulling fan and only cooling components that are directly in the thin stream of air, positive air pressure cause that turbulence that you mention which causes the air to move in a wider path around the case. Imaging pulling a chain across the floor, the chain is as thin as it can be as is negative pressure, now push a chain across the floor, it spreads out to a wider path. Does this statement makes any sence, "Denser Air Has A Higher Capacity To Absorb Heat And A higher Rate Of Absorbsion", if you agree with that statement then how do you make air denser?
December 21, 2009 1:27:46 PM

bruhthakuga said:
In my research I have come to know it is called Positive Air Pressure and it is usefull

spelled usefuL wrong
December 21, 2009 1:32:39 PM

look, bruhthakuga, people amswered your Q, so there! pushpush sucks, pushpull rocks!
December 21, 2009 6:39:03 PM

Uh! No! They Didn't, they talk down to me with speculation and conjecture trying to sound smart. No one actually listen to what I said they only looked for something loose to pull off and shake at me. More fans blowing into a case than pulling out is better and to be sure, is effectively PUSH PUSH, and is POSITIVE AIR PRESSURE. My question was, "Anyone experimented with Push+Pull vs. Push+Push Dual Fans on a Heat Sink?", not have anyone thought about it, dreamed about it, talked about it, hate it. You cyber people are hateful small people that get on forums to look for opportunity to be the big dogs. Some of you guys were probably locked in your lockers, had you ears flicked, lunch taken, and all around treated badly in "Real" life and so you are trying to get the sense of getting even or something to that effect. You feel impotent but hate makes you feel powerful, doesn't it. That disrespectful treatment of people that don't agree with you don't add to you. You perfectly could've found a post that say what you want to hear but truly you want to find place to feel powerful with your strong hateful words, I feel sorry for you, I really do.
a b K Overclocking
December 21, 2009 6:39:11 PM

That is a nice theory, now back it up with some data. Air is a liquid not a solid so it doesn't work that way at all. I have seen tests with types of systems using smoke to show the air flow. It works nothing like your analogy.

You can tell me an apple is an orange all you want, but when all the data says its really an apple and I have seen it with my own eyes your going to have a hard time getting me to believe it.

a b K Overclocking
December 21, 2009 6:44:13 PM

They only person I see being hateful and disrespectful is you. We are simply having a discussion, your the one getting mad.

December 21, 2009 7:00:05 PM

sorry i even said something, but pushing two fans towards each other is kinda useless seeming!
December 21, 2009 7:00:43 PM

just trying to help, g*d d*mn it!
December 21, 2009 9:29:49 PM

Am not angry at all, I am not going to give you free rent in my head, I am so easy going that as soon as I click the submit button I don't even know you exits till I get an email and if ever you approach within a million miles of that action I will just go to my profile and stop the alerts from this post. Will probably do it anyway because there isn't anyone mature with a good electro/mecanical sense responding. Yea! Yea! I expect that you'll make some brags about something you read about someone else like you also did or know it but you make it clear that you don't really know the ology behind cooling, you only copy what you read others do but you cannot really see in you minds eye and truly understand the physics of what is going on. I only asked the question but I know it works if the math is correct.
December 21, 2009 10:01:59 PM

bruhthakuga said:
Am not angry at all, I am not going to give you free rent in my head, I am so easy going that as soon as I click the submit button I don't even know you exits till I get an email and if ever you approach within a million miles of that action I will just go to my profile and stop the alerts from this post. Will probably do it anyway because there isn't anyone mature with a good electro/mecanical sense responding. Yea! Yea! I expect that you'll make some brags about something you read about someone else like you also did or know it but you make it clear that you don't really know the ology behind cooling, you only copy what you read others do but you cannot really see in you minds eye and truly understand the physics of what is going on. I only asked the question but I know it works if the math is correct.


Your original assumptions are incorrect, so therefore you built a maths construct to support your original assumption. Bad science. Yes, denser atmosphere will support more heat transfer than vacuum, for instance, but if you have a static airmass above your heated surface then once that airmass absorbs all of its heat... Well I hope you get the idea. But a moving airmass of lesser density that is not in a closed system will constantly move the heat absorbed away from the heating element, thus keeping the heated surface cooler. You need to go back to your basic laws of thermodynamics...

The short of it is that a push-pull configuration will be far more efficient at heat removal even if it is less efficient at heat absorption.
December 21, 2009 11:15:53 PM

croc said:
Your original assumptions are incorrect, so therefore you built a maths construct to support your original assumption. Bad science. Yes, denser atmosphere will support more heat transfer than vacuum, for instance, but if you have a static airmass above your heated surface then once that airmass absorbs all of its heat... Well I hope you get the idea. But a moving airmass of lesser density that is not in a closed system will constantly move the heat absorbed away from the heating element, thus keeping the heated surface cooler. You need to go back to your basic laws of thermodynamics...

The short of it is that a push-pull configuration will be far more efficient at heat removal even if it is less efficient at heat absorption.


To clarify what you are saying, if there are two setups both of sufficient air flow but one with high density air flow the other with lower air flow density that the lower air density setup will cool better? Keep in mind that I am talking about a cooler similar to this Scythe Ninja Copper which allows air flow through four sides
As you can see if you put PUSH-PUSH on this cooler it will not cause a very much higher air pressure than PUSH-PULL as the air will just come out the sides.
I am not supporting this Scythe Ninja Copper as there are many others that will allow air flow out the sides.
December 22, 2009 12:04:56 AM

bruhthakuga said:
To clarify what you are saying, if there are two setups both of sufficient air flow but one with high density air flow the other with lower air flow density that the lower air density setup will cool better? Keep in mind that I am talking about a cooler similar to this Scythe Ninja Copper which allows air flow through four sideshttp://images.bit-tech.net/content_images/2008/06/scythe-ninja-copper/14.JPG
As you can see if you put PUSH-PUSH on this cooler it will not cause a very much higher air pressure than PUSH-PULL as the air will just come out the sides.
I am not supporting this Scythe Ninja Copper as there are many others that will allow air flow out the sides.


You are NOT clarifying my statements, as they could have not been more clear than when I made them. More airflow, albeit at slightly lower pressures, will result in more efficient cooling. Perfect airflow conditions would be high velocity laminar airflow.
December 22, 2009 1:30:02 AM

I am sorry, I didn't mean that I was clarifying your statement I mean that I was clarifying my understanding of it. Let me ask you a question please, "if there are two setups both of sufficient, equal air flow but one with high density air flow the other with lower air flow density which will cool better?"
a c 86 K Overclocking
December 22, 2009 1:50:32 AM

bruhthakuga said:
Uh! No! They Didn't, they talk down to me with speculation and conjecture trying to sound smart. No one actually listen to what I said they only looked for something loose to pull off and shake at me. More fans blowing into a case than pulling out is better and to be sure, is effectively PUSH PUSH, and is POSITIVE AIR PRESSURE. My question was, "Anyone experimented with Push+Pull vs. Push+Push Dual Fans on a Heat Sink?", not have anyone thought about it, dreamed about it, talked about it, hate it. You cyber people are hateful small people that get on forums to look for opportunity to be the big dogs. Some of you guys were probably locked in your lockers, had you ears flicked, lunch taken, and all around treated badly in "Real" life and so you are trying to get the sense of getting even or something to that effect. You feel impotent but hate makes you feel powerful, doesn't it. That disrespectful treatment of people that don't agree with you don't add to you. You perfectly could've found a post that say what you want to hear but truly you want to find place to feel powerful with your strong hateful words, I feel sorry for you, I really do.



Boy that was fun! Ohh well, it happens. Take a pill.
December 22, 2009 2:12:15 AM

bruhthakuga said:
I am sorry, I didn't mean that I was clarifying your statement I mean that I was clarifying my understanding of it. Let me ask you a question please, "if there are two setups both of sufficient, equal air flow but one with high density air flow the other with lower air flow density which will cool better?"


Were I building a computer room for a data warehouse, I'd probably go for a 3 to 5psi positive pressure ventilation system. Why? Keeps the dirt out. But within the confines of a computer case, this would be very difficult to achieve, short of restricting over all airflow. I am sorry, but the laws of thermodynamics and fluid mechanics are not really on your side here. Anything that you do that restricts airflow is defeating your primary objective, which is to remove as much heat as possible in the shortest time possible.
a b K Overclocking
December 22, 2009 10:19:01 AM

Just seal up your case tight with two passages for air to move into or out of the case, both with valves. Make one small and the other very large. Connect a pump to the small one and ensure the valve on the large hole is tightly shut. Pump air into the case until it is about to explode, then close the intake valve and shut off the pump and quickly open the large valve. Rapid decompression = cooling.

Connect everything up to a nicely tuned timer and automate the process. Air cooling at its best. There is no need for water.
December 22, 2009 10:50:56 AM

randomizer said:
Just seal up your case tight with two passages for air to move into or out of the case, both with valves. Make one small and the other very large. Connect a pump to the small one and ensure the valve on the large hole is tightly shut. Pump air into the case until it is about to explode, then close the intake valve and shut off the pump and quickly open the large valve. Rapid decompression = cooling.

Connect everything up to a nicely tuned timer and automate the process. Air cooling at its best. There is no need for water.


See System Spec>cooling. Taking the whole bottle of pills is not out of question.

Intel OEM, Case side off, PC Duct Taped to Window A/C unit



December 22, 2009 11:25:11 AM

bruhthakuga said:
Anyone experimented with Push+Pull vs. Push+Push Dual Fans on a Heat Sink?

I know that Push Push give higher air pressure thus denser air (compressed) and that absorb heat more readily, However, depending on sink dims it also may give slower air speed which tends to negates the gains. On push push if your sink is close to cubed shape then the intake and exhaust area will be the same and it seems to that this is where a push push is better, yes push pull will still have somewhat faster air speed but very little but it seems to me that the better heat dissipation of the denser air will out rank the speed? This is all my crazy little head flatulating.


If I had a sink that is 120 X 120 X 60 then with push push the exhaust area will be half of what the intake area, is this where one should choose a Push pull set up? What do the experimenting prove?


Look butttmunch or whatever your name is...

Why don't you just do it and see what happens.

You WILL NOT get enough positive pressure from CASE FANS to make a bit of difference. You're better off moving the air faster through the case. And the shortest path crap your talking about isn't all that bad either because it will lower the ambient temps of the case!
a c 224 K Overclocking
December 22, 2009 12:36:03 PM

bruhthakuga said:
co⋅nun⋅drum
  /kəˈnʌndrəm/ Show Spelled Pronunciation [kuh-nuhn-druhm] Show IPA
Use conundrum in a Sentence
–noun
1. a riddle, the answer to which involves a pun or play on words, as What is black and white and read all over? A newspaper.
2. anything that puzzles.

Here's a a Riddle for you num drum:)  "What compresses air on one side and causes a vacuum on the other side and it has blades that spins? Clue, it starts with "F" and ends with "AN"? Next time you watch the news pay attention to the word "Pressure" and see how it relates to air temperature. Also think of just how much pressure difference they are talking about. You cannot live without compressed air also contrarily to popular opinion air pressure is alway varying, when you feel wind that is a sign of varying air pressure.

Most sink have six side two of which air cannot flow through so if you have a fan on two sides in a push push configuration that still leaves two sides for air to flow out of and the point is to have them "Fight Each Other" to a point to raise pressure but remember, there is still two side for air to flow out of. Now pay attention next time before you blow sNOT all over someones post.



Conumdrum, was not trying to insult you with his post, if he was, he'd have done a much better job of it!

You're new here and taking insulting attitudes towards others opinions is not a great way to make friends here, you started this thread as an open invitation to others opinions, with really nothing but speculation and theory, and you hadn't even ran your own tests?

I am one using a push pull configuration, and in my situation the added pulling fan made a 1c drop difference, so it may not have been a drastic improvement but added to the 9c drop I had acquired by lapping my heat sink base and my CPUs heat spreader, which gave me a solid overall 10c drop.

All this talk about pressure really doesn't relate to increased cooling, what matters to increased cooling is getting the heated air out of the case, preferably in as smooth a flow as possible to avoid hot pockets of air turbulence, having 2 fans pushing against each other will cause turbulence inside the case.

Having 2 fans pushing against each other is going to decrease each fans output, making the fan work harder and build up heat in the fan motor, the fan motor is cooled by the fan blades pulling in the fresh air, but the pressure will cause the fans to run at impeded performance, running hotter, and basically shorten the lifespan of the fans.

That will happen even with the heat sink you displayed, but you obviously weren't taking into consideration all heat sinks don't allow side airflow anyway, my Xigmatek for example has closed sides and a push push on that heat sink would completely be a disaster.

Maximum air cooling is directly gained by airflow, having the proper air flowing over the heat sink fins so the air can pick up the heat and remove it from the fins and exhaust it from the computer, now fan speed is important here because any air cooled heat sink has a airflow sweet spot, being a balance of the air flow over the fins to the heat transfer to the air.

The same thing happens with water cooling, different water blocks are designed for different flows, if you push the water through too fast with a low pressure water block, the heat doesn't have enough time to transfer to the water, thus seriously decreasing the cooling.

High pressure, high flow water blocks however are designed to transfer the heat faster, so they benefit by a faster water flow, and the same principle applies to airflow over a heat sink.

If your theory were viable we'd have a host of push push heat sink coolers available to us on the market, do you really think each heat sink manufacturer out there hasn't already tried every approach they could think of, to have the best air cooler on the market period.

The worst thing you can do for your cooling is purposely create turbulence inside your case, to impede the airflow through it.


a b K Overclocking
December 22, 2009 4:30:20 PM

"Yea! Yea! I expect that you'll make some brags about something you read about someone else like you also did or know it but you make it clear that you don't really know the ology behind cooling, you only copy what you read others do but you cannot really see in you minds eye and truly understand the physics of what is going on. I only asked the question but I know it works if the math is correct."

If this was aimed at me I can assure you have done plenty of my own testing along with reading stuff others have done and talking and helping others with it as well. I have not done this specific test because based on some others I have done I am pretty confident it won't work.

You have yet to back up any of your theories with any data or perform the test for yourself and post your findings. You sort of sound like an engineer to me. You have that "if it works on paper it must be real" kind of attitude. Then again if you were an engineer you would know just how complex the math for thermal dynamics really is. To calculate what you suggest would require an awful lot of math and a fair amount of data to base it on. At least for it to be accurate.

I have a simple cooler like that on my computer, I may just take it apart and try some different fan configurations and see what happens. Actually I have done most of them already, I just didn't try that one because I was pretty sure it would not work based on other tests so I didn't want to waste my time on it.

a b K Overclocking
December 22, 2009 5:47:25 PM

This is nonsense, all the OP has to do is try both setups and compare temps and he is done. Not sure why he blew this out of proportion....

a b K Overclocking
December 22, 2009 6:22:05 PM

Years ago a two aeronautical engineers that worked with wind tunnels at NASA took a look at pc case fans. They actually wound up writing a white paper that was full of technical information. They also answered quite a few questions at one of the forums. I am kicking myself in the pants for not bookmarking the information.

I am going strictly by memory. The engineers suggested that a slight negative air pressure was just a little bit better than positive pressure. The stressed the importance of excellent airflow to remove heat from a pc case and talked about creating a wind tunnel effect by lining up an intake fan on the front of the case, the cpu heatsink fan, and the exhaust fan on the rear panel. In addition the wind tunnel effect could be improved with some additional ventilation and airflow to create what I think was called a venturi effect.

During the forum discussion a question was asked about adding a second fan on the back side of a cpu heatsink for a push/pull configuration. The engineers replied that results would depend on the distance between the fan on the back of the heatsink and the fan on the rear panel. The problem was the fans would be out of synch and the turbulence that was created would actually impede the efficient removal of hot air. The engineers stated the opening between the two fans would have to be at least one inch and preferably one and one half inches for it to work efficiently.

I have followed their advice and have had outstanding results ever since.

bruhthakuga - In looking at your original post, I see a flaw. With a push/push configuration the heated air is forced to move in say 3 of 6 possible directions instead of one direction. You did not address how the hot air was going to be removed from the case. Would you consider the possibility that a wind tunnel effect with unimpeded airflow might be more efficient at removing hot air?

!