Need help with airflow

Discussion in 'Building a new PC' started by conb123, Jun 11, 2010.

  1. conb123

    conb123 Member

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    Hiya

    I am using a core i7 860 @ 3.5GHz CPU in an antec 300 case. My cpu has a noctua nh-u12p SE2 dual fan cpu cooler cooling it. The air from this clows upwards out of the exhaust fan at the top of my case. I also have an intake fan at the front of the case pulling in air from the front. Now my question is, would airflow be better with the rear exhaust fan pulling in air towards the heatsink or as an exhaust fan blowing it out. I sketched up some drawings to try and clear things up, sorry for how awful they are.

    This:

    [​IMG]

    Or this:

    [​IMG]
     
  2. KillerBug

    KillerBug Active member

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    Unless you have a basic video card and only a couple drives, I think option 2 would give you lower CPU temps; but it may raise other temps in the process, most notably the chipset and ram.

    I am assuming that you have a power supply with a nice 120mm exhaust fan, only one 120mm fan in front, and that you have no side fan installed.

    If it were me, I would put a second 120mm fan in the front (2 front intake fans), set the rear and top fans as exhaust, and I am not sure what I would do with the side fan...I guess I would just run at full load for a while in both modes and see what produces better temperatures. I would probably also install a couple of blower fans to cool the cards...but I have a lot of cards making a lot of heat.
     
  3. conb123

    conb123 Member

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    Ok yes, I am using a Corsair VX 550w psu, the front intake fan is a 120mm Xilence Red Wing (http://www.novatech.co.uk/novatech/prods/Components/Cooling/Fans/100mmplus/Xilence/REDWING120MM.html), my video card is an ATI Radeon HD 4850, so not that basic. I will try option 2 for a while and maybe buy a new fan and try your suggestion thanks.
     
  4. cee43ja1

    cee43ja1 Active member

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    top and rear fans should be exhaust, and the NH-U12P should be blowing to the rear exhaust fan instead of the top.
     
  5. conb123

    conb123 Member

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    To the rear? Why? I thought if it blew upwards it would also pull heat from other components such as video card and psu?
     
  6. cee43ja1

    cee43ja1 Active member

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    with the vx550 fan facing upwards, it's acting as a exhaust fan already, when it kicks in. and with the cooler being vertical, the ram gets cooled since the fan from the NH-U12P is pulling the air away from the ram. also, with the cooler in the horizontal position, you're forcing more hot air into it because the heat from the gpu is being captured by the cooler's fan.
     
    Last edited: Jun 11, 2010
  7. conb123

    conb123 Member

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    Ah I see, that does seem to make a lot of sense, but, my gpu fan is facing downwards, it won't be cooled like that will it?
     
  8. conb123

    conb123 Member

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    Oh my gosh! You were certainly right CPU temperature in BIOS has dropped to 26 celcius from about 30 and system is at 24 celcius.
     
  9. conb123

    conb123 Member

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    Actually scratch that, it might just be because of my room temperature, I shall run some tests and report back.
     
  10. conb123

    conb123 Member

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    Sorry if you have double post rules here, but I thought I'd say, the temperatures seem to be pretty low, idle temperatures in Windows 7 (only using because sensors don't work for my board in linux) was around 29 - 31 celcius. I ran prime95 for a little while (I know your supposed to leave it running for a while but didn't want to burn out the chip) on blend and it reached temperatures of about 63 celcius. Seems a little high still, might have to re apply my thermal paste to at some point but thanks for all your help.
     
  11. jhonsadin

    jhonsadin Member

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    I personally think that there were no problem with that i had made several design kinda you i am gonna test it today and post it here later..
     

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