Rear case fan. Intake or exhaust?

Discussion in 'polls' started by ThunderZ, Mar 11, 2009.

?

Intake or exhaust

  1. Intake

    2 vote(s)
    6.5%
  2. Exhaust

    29 vote(s)
    93.5%
  1. ThunderZ

    ThunderZ Registered Member

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    I have always set the rear case fan to exhaust. But recently I have read about and come across PCs that have them as intakes. How are yours\do you set yours?
     
  2. boonie

    boonie Registered Member

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    How many fans do you run Thunderz?
     
  3. GES/POR

    GES/POR Registered Member

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    The logic of a rear intake fan goes by me, in that case the front fan(s) should exhaust
     
  4. ThunderZ

    ThunderZ Registered Member

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    On my mid-tower size case, counting the processor and PS, 5. The rear is set to exhaust. Any PC I have ever built had the rear case used as an exhaust.

    The tower sets on a small table I got from a place I used to work. There was a plastic parts tray setting in it. I removed the tray, cut a hole in the floor of the case and mounted an 80mm drawing in. I used a 92mm to 120mm fan\funnel adapter to put a larger fan on the processor heat sink. Also used a 80mm to 120mm funnel mounted to the rear outside of the case to put a 120mm instead of 80mm case fan for exhaust. The PS is a 2 fan model.

    The Nvidia 7600GT had a GPU fan but I went passive since it is located almost directly over the 80mm in the floor of the case.
    GPUZ says the card is at 34 to 35C at idle. Have never seen it go over 41C after several hours of gaming. World at War.
    Core Temp. says my dual core Athlon 4200+, stock clock of 2.2GHz is running at 36 and 35 respectively. Have never seen it go over 42C.

    Room temp is around 22C.
     
    Last edited: Mar 11, 2009
  5. ThunderZ

    ThunderZ Registered Member

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    Agreed.

    Had never thought of turning the fan any other way but as an exhaust.

    The whole reason I asked is because seeing a fan running this way was completely new to me.
    Had even read of an instance of the processor heat sink fan being turned to blow up, away from, instead of down onto it. I was going to question the persons` reasoning for it but it was a several year old thread.
     
  6. yashau

    yashau Registered Member

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    If that's the case then the exhaust at the front should be high up as most cases got front fans that are below as the top area is reserved for the 5 & 1/2 drive inch bays. When the air gets circulated inside the case it will get hot! The exhaust needs to be elevated as hot air will rise to the top. There's another problem of the PSU as well. All PSU's as far as I know are exhausts. If you keep an intake right near to the PSU it will prevent proper air circulation inside the case. Unless you can hotwire the PSU to run it's fan in the opposite direction.
     
  7. TairikuOkami

    TairikuOkami Registered Member

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    http://forums.techpowerup.com/showthread.php?t=42853

    As pointed out in the article in does not matter as long as the airflow is in one direction only and cold air intake is at lowest point and exhaust at highest point.

    I have this case and I have on it 3 intake fans in front and 2 exhaust fans, one at the rear and the second at the top, there are also 2 exhaust on PSU. :)
     
  8. Carver

    Carver Registered Member

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    I have 2 120 fans in front that are intake; one 120 fan on top that is exaust and one 120 fan in the rear that is exaust. The size and the number of fans I think should be balenced and if posable the exaust at least one exaust should be on top, I think the perfect place would be next to the PSU to draw away the heat as well as venting the rest of the heat. Perhaps I am wrong and the rear fan could be a intake as well, but than you would need 2 120 fans on top or 1 fan on top twice as big to balence the CFMs again.
     
  9. boonie

    boonie Registered Member

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    Sweet case! :thumb:
    I just picked a Storm Sniper up for my new build. Intake is 200 fans on front and side, 140 on bottom.
    Exhaust is 200 on top and 120 in back.
    PSU intakes from bottom and exhausts in back.
     
  10. Cerxes

    Cerxes Registered Member

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    In my latest build I've used Antec Solo which has a very good design regarding cooling & low noise escape. When it comes to the rear case fan it would be best to use it as an exhaust since it's normally close to the PSU and therefore will blow some of the hot air back into the case if used as intake. Try using 2.5" hdd's instead of 3.5" for reducing heat & noise (vibrations).

    /C.
     
  11. YeOldeStonecat

    YeOldeStonecat Registered Member

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    That's the key. "balance" things too, I prefer exhaust only. Having too many intakes disrupts the airflow.

    I prefer to have my hard drives mounted so that they're right behind the air intake...so air being sucked into the case flows over the drives...helping to cool them a bit. Then diagonally up/across the motherboard..and out the exhaust.

    I like a single large quiet slow RPM exhaust fan in my case.