# fan out-take vs intake



## jrm249

ordered a fan for my new rig.  not sure how temps look for only having 2 fans, but i want more.  (cpu is around 25-29 idle and 38-43 on load.)  i have a side panel case fan blowing air directly onto the motherboard/ram, seems to kinda be working against the processor's fan but i hear intake is the best way to do the side panel.  I have only 1 out take fan right now, a PCI slot fan in the rear.  it sucks air off the video card mainly, but also gets the excess heat a little.  probably is the strongest/most efficient fan. 

so i have room for a fan on the back still, and on the top of the case.  im thinking 2 out takes and 1 in take will be worse than 2 intake and 1 out take.  but the top fan would make more sense to be out take since heat rises.  any ideas?


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## porterjw

Usually, the best way is front-lower intake and upper-rear exhaust. Depending on how your system is set up (airflow, cable-maintenance, interior accessory arrangement) a side fan might do more harm than good by disrupting the flow inside the case. I would experiment with a few ways, but always with keeping the front-intake/rear-exhaust.


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## Computer_Freak

Yes the best is front intake, back exhaust

If you want your CPU temps to drop, what you do is take your cone that comes standard with the case (the one that is there to give "fresh air" to the CPU) and stick a intake fan behind it.

The cold air will blow DIRECTLY onto the CPU. Ive dropped temps by +- 7 from a tiny 80mm fan and stock cooler. And the best thing is that it only feeds the CPU air, and there is no "crosswind" cause of the cone. So no air disruptions, meaning better air flow


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## jrm249

there's no room for a front fan on my case.  just the side panel, top, and a rear.  

does a reverse set up work?  like back is blowing in, side is in, and top is blowing out hot air?


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## porterjw

Typically no, but what model case do you have?


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## cohen

i have a funnal over my CPU, a out take fan in the back of my case, and a small area with no fan, and it works great, my CPU sits around 25C idle, 30C to 40C on a load, which is normal for a CPU.


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## Computer_Freak

jrm249 said:


> there's no room for a front fan on my case.  just the side panel, top, and a rear.
> 
> does a reverse set up work?  like back is blowing in, side is in, and top is blowing out hot air?



The side will be just for your CPU... put the cone (funnel) over the side, wit a fan behind it, so your CPU ONLY gets cooled (intake). 

Also If your CPU gets cooler, the rest of the components will run cooler (thats what i have found).

Then i think the best will be to have the Top exhaust and the back exhaust as hot air rises. No need to circulate hot air, rather just vent the hot air out and let new air heat up.


And your Case does have a front slot. My old P3 had a place in front (look from the inside of your case.) You will find it. 

The best thing is to get Hardware monitor (made by the same guys as PCwizard) and use it to see temps. Then try different combos (Just make sure to use the cone and a fan as input, to blow DIRECTLY and ONLY on the CPU.

http://lib.store.yahoo.net/lib/directron/atxb8klwss02.gif

You see the funnel there? as it is take it out, put a INPUT fan behind, connect them and put it back. It is the best for CPU cooling


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## tlarkin

I want to say Maximum PC did an article on air flow and cases and fan deployment.  They used a fog machine to show how the air flowed in each system.  If you could google and dig out the article (as it is several years old) it could help you out.


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## porterjw

> And your Case does have a front slot.



Rather presumptuous seeing as how (s)he never mentioned what kind of case they had. Many don't have room for a front fan.



> You see the funnel there? as it is take it out, put a INPUT fan behind, connect them and put it back. It is the best for CPU cooling



Depends on the system, room temp, CPU speed, CPU usage, etc. Way too many variables. The added noise from the airflow wasn't worth the 1*C cooler my CPU ran - just a hassle removing it and going back to the plain old funnel.



> I want to say Maximum PC did an article on air flow and cases and fan deployment.



Do you have a link? I'd love to read it. I tried searching a few variations, but all I got were the MaxPC forums (which, from the looks of it, are light years behind CF).


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## Computer_Freak

imsati said:


> Rather presumptuous seeing as how (s)he never mentioned what kind of case they had. Many don't have room for a front fan.
> 
> Depends on the system, room temp, CPU speed, CPU usage, etc. Way too many variables. The added noise from the airflow wasn't worth the 1*C cooler my CPU ran - just a hassle removing it and going back to the plain old funnel.



I dont mind the noise (then again fans here are expensive) If you get a silent one....

Also my system dropped 5-10* with the fan, and when i play CoD4, i dont get PC lag anymore (used to be a problem)


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## liamhenning

i have an exhaust fan under my graphics card.

im glad i got it now. the amount of heat it throws out of the case is good for the £4 that i payed for it. Defo a good buy.

i also have a side case fan blowing onto my mobo. It seems to keep eveything nice and cool. but i also have a case fan sucking in through the front vents. and blowing out through the back to create a flow through the case.


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## oscaryu1

Side - In
Side bottom - In
Front - In

Top - Out
Rear - Out

Heat rises. Another reason why the PSU is on top.


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## Computer_Freak

oscaryu1 said:


> Side - In
> Side bottom - In
> Front - In
> 
> Top - Out
> Rear - Out
> 
> Heat rises. Another reason why the PSU is on top.



Well its good for teh case, bad for the PSU....

The PSU will suck out the hot air, but the PSU itself also needs cool air.


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