# Fan Placement Help



## welly321 (May 19, 2009)

Ok guys, so the side fan on my CM 690 is just too loud and im moving it somewhere else. Its not the fan because ive tried three different fans and they all make the same wierd buzzing noise. So i have one fan in the front ( intake), one on top (exhaust), one in back (exhaust), and the side fan that im moving. Where do you recommend i move it and intake or exhaust...im guessing intake so i have 2 of each.  Thanks in advance! (there is a spot to mount on the bottom and a spot on top and ive heard its easy to mount another in front on this case)


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## Th0rn0 (May 19, 2009)

Intake fans should be front, side and bottom.
Exhaust fans should be back and top.

Thats all you really need to know.

I do recommend having as many intake as your case will take.


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## welly321 (May 20, 2009)

ya thanks i ended up redoing my cable management and putting the fan on the bottom of the case... i had to ghetto mod the fan with zipties to stop it from vibrating but its cool now. No change in temps though


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## mlee49 (May 20, 2009)

Bottom would be my suggestion, any pics?

Perhaps just try running without the fan, check temps and see if you have any increase.  A better investment would be a $35 cpu heatsink w/fan and then not worry as much about loud case fans.


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## a_ump (May 20, 2009)

not to steal the thread, but is more intake better or exhaust better? i've always wondered this and just kept it balanced, well 3 out, 2 in.


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## mlee49 (May 20, 2009)

a_ump said:


> not to steal the thread, but is more intake better or exhaust better? i've always wondered this and just kept it balanced, well 3 out, 2 in.





Th0rn0 said:


> Intake fans should be front, side and bottom.
> Exhaust fans should be back and top.
> 
> Thats all you really need to know.
> ...



What he said 

Some people say have a balanced airflow rate in as out, but I'm not that picky.


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## timta2 (May 20, 2009)

The noise is from the metal in the side panel vibrating by the way. Do a search and you will find several discussions about it. You could try putting some (rubber) spacers between the fan and side panel and closing the gap with transparent (packing?) tape. That is what I was going to do until I cut a window in the side panel with a fan mount.


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## welly321 (May 20, 2009)

Yea the side fan noise was annoying but i dont even need a side fan. My MAX load temps dropped 2 degrees by moving the side fan to the bottom.


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## Mussels (May 20, 2009)

a_ump said:


> not to steal the thread, but is more intake better or exhaust better? i've always wondered this and just kept it balanced, well 3 out, 2 in.



slightly more in than out. positive air pressure keeps dust to a minimum.


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## Pinchy (May 20, 2009)

Mussels said:


> slightly more in than out. positive air pressure keeps dust to a minimum.



Isn't it slightly more out than in?

The inside of your case will always be higher than room temperature, so you want to exhaust that hot air out of the case. If you have more out than in, your keeping inside the case closer to room temperature (cooler) as air will always be there, even if you dont have intake fans. 

Thats what I have been told and it just seems logical, lol.


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## Mussels (May 20, 2009)

Pinchy said:


> Isn't it slightly more out than in?
> 
> The inside of your case will always be higher than room temperature, so you want to exhaust that hot air out of the case. If you have more out than in, your keeping inside the case closer to room temperature (cooler) as air will always be there, even if you dont have intake fans.
> 
> Thats what I have been told and it just seems logical, lol.



no logic at all to that. More air in = more cold air in and higher air density, if you want to go with the weird logic.


More air in = positive air pressure = excess air leaks out every gap and crack. This blows dust OUT of those cracks, away from the case.

negative air pressure works in reverse - it sucks the dust in from those cracks.


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## welly321 (May 20, 2009)

So right now in my CM 690 i have an exhaust at the back, an exhaust on top, an intake in front, and an intake on the bottom. Where do you recommend i put another intake? Side?


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## Mussels (May 20, 2009)

welly321 said:


> So right now in my CM 690 i have an exhaust at the back, an exhaust on top, an intake in front, and an intake on the bottom. Where do you reccomend i put another intake? Side?



side intake sounds good. dont forget to count your PSU fan when balancing airflow.


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## DaveK (May 20, 2009)

Mussels said:


> no logic at all to that. More air in = more cold air in and higher air density, if you want to go with the weird logic.
> 
> 
> More air in = positive air pressure = excess air leaks out every gap and crack. This blows dust OUT of those cracks, away from the case.
> ...



This kind of explains my dust problem, 2 120mm intakes, 1 120mm and 1 200mm exhaust...I need more intakes 

What if I just turned up the intake fans and kept the exhaust ones on low?


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## Mussels (May 20, 2009)

fan control will work. its the airflow that matters, not the actual number of fans.


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## welly321 (May 20, 2009)

My power supply only has one fan so its just blowing out from only the power supply...that doesnt count does it? ...What i mean is inside the case the power supply is solid so no air is getting into from the case...


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## Mussels (May 20, 2009)

welly321 said:


> My power supply only has one fan so its just blowing out from only the power supply...that doesnt count does it? ...What i mean is inside the case the power supply is solid so no air is getting into from the case...



the PSU isnt solid. it sucks are in from within the case, and blows out the back.

PSu's with an 80mm exhaust at the rear passively suck air from within the case, 120 and 140mm PSU fans suck air within the case and passively blow it out the back. Its the same end result, one mroe exhaust fan.


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## welly321 (May 20, 2009)

Wow really? So it kinda sucks case air in through the cracks or something? And my doesnt blow out the back, it blows out the bottom. Thanks for all your help mussels


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## Mussels (May 20, 2009)

welly321 said:


> Wow really? So it kinda sucks case air in through the cracks or something? And my doesnt blow out the back, it blows out the bottom. Thanks for all your help mussels



http://www.coolermaster.com/uploads/product/products_highlight/file1206081916890.jpg

This is your PSU, according to your specs.

That sucks air in that fan, and blows it out the mesh at the rear.


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## welly321 (May 20, 2009)

Wow now im really confused...so that fan is an intake and it goes out the back? ..i thought the fan on the bottom was an exhaust...so this counts as an exhaust or intake? lol
this is my power supply i think its different from the one you posted...http://www.newegg.com/Product/Product.aspx?Item=N82E16817171032


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## mlee49 (May 20, 2009)

The fan on the bottom of your PSU takes the air from your case that pushes air out. So technically it's an exhaust fan.


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## welly321 (May 20, 2009)

Ok then looks like i definitely need to add another intake fan on the side...thanks for the help guys.


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