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Power supply exhaust fan direction in top mounted cases.

I've noticed that a lot of cases now seem to have bottom mounted locations for power supplies. I'm guessing that's for allowing the hot air to rise and exit through the back exhaust of the case. That made me question if I put my PSU in correctly in my case. I have a case with a top mounted power supply and my power supply is:



As you can see from the picture, the exhaust of the power supply is pointing up, so I put it in that way into my (top mounted) case. However, there is very little room between the top of the PSU's exhaust and the top of my case. Am I supposed to mount the PSU so that the exhaust fan points down (so the hot air gets blown to my back case exhaust fans)? I assumed I was supposed to mount the PSU exhaust fan up because if I inverted it, the lettering and words on my PSU are upside down.

Thanks!
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  1. Best answer
    Top mounted PSUs are generally meant to have an air intake on the bottom and to suck the hot air from the components into the PSU and then suck it out the back of the case with a second fan in the PSU.

    I have seen one application where a top mounted PSU could draw in air from the top of the case and send it out the back (and indeed the back was intake and the front of the case was exhaust on that setup), but I would guess like 0.01% of people have such a setup, if that.

    Anyway, if you are top mounting the PSU, I would put the open side down, because it is most likely meant to be that way, regardless of the label direction.

    Better yet, buy a better case that lets you bottom mount the PSU instead. It will do wonders for the lifespan of the PSU. It will probably better cool the internal parts too.
  2. PSU's take in the air with their fan. It doesn't matter really that the fan takes in the air from your case as it's meant to be that way with a top mounted PSU case.
    You need to reinstall the PSU with the fan pointed inside(down) in the case.
  3. I didn't realize that the top fan is actually an intake fan, but that does make a lot more sense.

    Thanks!
  4. Raiddinn said:
    Top mounted PSUs are generally meant to have an air intake on the bottom and to suck the hot air from the components into the PSU and then suck it out the back of the case with a second fan in the PSU.

    I have seen one application where a top mounted PSU could draw in air from the top of the case and send it out the back (and indeed the back was intake and the front of the case was exhaust on that setup), but I would guess like 0.01% of people have such a setup, if that.

    Anyway, if you are top mounting the PSU, I would put the open side down, because it is most likely meant to be that way, regardless of the label direction.

    Better yet, buy a better case that lets you bottom mount the PSU instead. It will do wonders for the lifespan of the PSU. It will probably better cool the internal parts too.

    Very informative reply Raiddinn. :D You summarize well to conclude why it's so important to have sufficient air flow.
  5. Best answer selected by coderunner.
  6. Glad to assist.
  7. coderunner said:
    I didn't realize that the top fan is actually an intake fan, but that does make a lot more sense.

    Thanks!

    you're welcome coderunner.
    That was just a photo of the PSU.
    Also, did you read any of the instructions that came with your PSU? Or at least the PSU should have some details on it
    about it's orientation of installation. :whistle:

    Anyway, as Raiddinn explained, most top mounted PSUs
    are mounted with the fan pulling air from inside.
    Most of the current gaming cases have the PSU mount at
    the bottom with the fan drawing air from outside the case.
    (I don't like that design yet as something could get sucked in
    that could cause problems)

    Anyway. Good luck with your PC!
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