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Intake or exhaust which is more important?

Last response: in Components
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January 13, 2013 11:17:53 AM

i'm using a micro-atx case,which has top mounted psu sucking air inside the case ,the question is i also have a 90mm fan to be fitted in my case so for which purpose should i use this fan intake or exhaust ?note that my case does not have top and bottom fan fitting options only side,front and rear.
a b ) Power supply
January 13, 2013 11:32:30 AM

it would make no difference as an intake as a 90mm fan would likely draw less cfm into the case than a 140mm psu fan extracts.
so in this case using both as extractors would be the more efficient use.
its actually best to have a balanced flow of in to out if you can create a slightly positive atmosphere in the case you will get less dust as it wont draw air in on every seam of the case. around the dvd or any other gap in the case.
the draw back of a positive pressure in the case is that cooling is slightly less effective.
to be honest there isnt much between the 2 methods other than a negative pressure needs more cleaning.

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January 13, 2013 12:28:24 PM

HEXiT said:
it would make no difference as an intake as a 90mm fan would likely draw less cfm into the case than a 140mm psu fan extracts.
so in this case using both as extractors would be the more efficient use.
its actually best to have a balanced flow of in to out if you can create a slightly positive atmosphere in the case you will get less dust as it wont draw air in on every seam of the case. around the dvd or any other gap in the case.
the draw back of a positive pressure in the case is that cooling is slightly less effective.
to be honest there isnt much between the 2 methods other than a negative pressure needs more cleaning.

my psu has a 120mm fan sucking air inside the case and i have fitted the 90mm green led fan at side at top of the cpu stock cooler.is this setup right ?or i should put my 90mm fan at rear as exhaust?
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a b ) Power supply
January 13, 2013 12:45:35 PM

all i can say is try for yourself... a little experimantation will give you the answers better than we can...
if you take the intake off the side you will reduce the cool air hitting the cpu but over all you may lower the whole case ambient. you could leav it be and the other components in the case may run warmer... like i say with such a limited option it would be better to test and see what gives the best balance
if you cant mount the 90 directly on the back of the case then forget it as an extractor. as putting it anywhere else except directly blowing out the top would cause to much turbulence in the airflow around the case.
it is better to pull air through the whole case in 1 direction rather than having multiple fans blowing in from every direction...
reason being is you will create paockets of still air that will heat up causing higher ambient case temps.

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January 13, 2013 1:00:28 PM

HEXiT said:
all i can say is try for yourself... a little experimantation will give you the answers better than we can...
if you take the intake off the side you will reduce the cool air hitting the cpu but over all you may lower the whole case ambient. you could leav it be and the other components in the case may run warmer... like i say with such a limited option it would be better to test and see what gives the best balance
if you cant mount the 90 directly on the back of the case then forget it as an extractor. as putting it anywhere else except directly blowing out the top would cause to much turbulence in the airflow around the case.
it is better to pull air through the whole case in 1 direction rather than having multiple fans blowing in from every direction...
reason being is you will create paockets of still air that will heat up causing higher ambient case temps.

so u are finally asking me to put that 90mm fan at rear ,okay consider it done .The reason i put that 90mm fan at side is due to the psu i thought that the psu fan would suck enough hot air inside my case.
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a b ) Power supply
January 13, 2013 1:03:44 PM

UGHHH WHAT ARE YOU DOING he didn't tell you to put it at the rear man. You need BOTH intake & exhaust, buy more fans, and if you can, bigger ones, 90mm is gonna have to be run at high RPMs to suck in air, and at that point its gonna be LOUD like a weed whacker. The PSU is only gonna be sucking in air FOR ITSELF, not for the entire case, so the rest of your components won't get cooled. Buy bigger fans if you can, and mount them as intake & exhaust cause you need it.
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January 13, 2013 1:27:15 PM

payturr said:
UGHHH WHAT ARE YOU DOING he didn't tell you to put it at the rear man. You need BOTH intake & exhaust, buy more fans, and if you can, bigger ones, 90mm is gonna have to be run at high RPMs to suck in air, and at that point its gonna be LOUD like a weed whacker. The PSU is only gonna be sucking in air FOR ITSELF, not for the entire case, so the rest of your components won't get cooled. Buy bigger fans if you can, and mount them as intake & exhaust cause you need it.

i can fit only 2x90mm fans at side but at rear i can fit one 120mm fans.so what and where do you want me to fix?and i don't bother about sound .i currently have only one 90mm fan which is not a PWM it's directly connected to psu's molex connector.i thought the psu would suck the air coming from the cpu stock cooler since my psu is top mounted.
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a b ) Power supply
January 13, 2013 1:37:25 PM

No, PSU will only cool itself. Use a 120mm fan for rear exhaust. Also, how many optical drive bay slots do you have? You can remove them, put in ones with dust filters so you can put a good intake fan there.
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January 13, 2013 2:11:44 PM

payturr said:
No, PSU will only cool itself. Use a 120mm fan for rear exhaust. Also, how many optical drive bay slots do you have? You can remove them, put in ones with dust filters so you can put a good intake fan there.

only one but even if i remove the optical drive bay i can't put a fan as there no option for it .
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January 13, 2013 2:18:00 PM

There should only one airflow, air going in and air going out inside the chassis.
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January 13, 2013 2:58:53 PM

aqe040466 said:
There should only one airflow, air going in and air going out inside the chassis.

finally got a 80mm fan free from my friend .fitted at side top of my graphic card as exhaust.so there is one intake at side for cpu cooler and one exhaust for gpu.is this combination okay?
going to fit an another 120mm fan at rear as exhaust.
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