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Is positive or negative pressure better for a pc case?

I have a corsair 900d with 3 front intake fans, 3 top exhaust, one rear exhaust, and 4 intake on the bottom left. I am watercooling. Would it be better if I changed my rear fans for intake?

Thanks :).
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More about positive negative pressure case
  1. If i was you, I would try to avoid pumping air directly on motherboards, GPU and stuff to avoid dust to get there. My Antec 300 has a dust filter in front so all intake is from front and the rest exhaust air.
  2. Positive pressure helps to keep dust out. Negative pressure may help with a negligible amount of cooling.
  3. Best answer
    the direction of air flow should go like this: Intake in front and lower front blowing to the rear, Intake at the bottom of case blowing up towards the top. Exhaust fan blowing out at the rear of the case, Top fans blowing out the top. Heat rises, there for push cool air in at the lower front forcing the heat out the top and rear.

    your fan setup is fine.

    As for which is better, there is are arguments for both sides but neither have a big advantage over the other. THe problem with a Negitive pressure set up is "It is much harder to filter some of the dust out". This is because being under negative pressure every where the air can seep in it will. this means cracks, crevices and gaps.

    A positive pressure has an advantage for filtering air quality because all cracks, crevasses and gaps have air pushed out of them so screen filters can clean more of the air. But in my experience positive does not cool quite as well but this is negated because the components get covered in dust faster causing them not to dissipate the heat as well. this means the negative system needs more maintenance
  4. mazooni said:
    I have a corsair 900d with 3 front intake fans, 3 top exhaust, one rear exhaust, and 4 intake on the bottom left. I am watercooling. Would it be better if I changed my rear fans for intake?

    Thanks :).


    Positive or negative .. can do either..
    You can push air out of case.. forcing cool air to be sucked in..(negative pressure)
    or can pull cool air in.. forcing the warm air out (positive)
    But makes more sense to use positive.. and ensure the stuff you pull in is filtered.. to reduce dust intake
    if you do negative.. you not sure where air is being pulled in from - so difficult to manage the dust.

    HTH
    Cheers
  5. After reading what everyone said I am pretty sure I want to leave it as is because the only thing I was considering changing in the first place was the rear fan from exhaust to intake but the rear is the only place of my case that is not dust filtered. Also the rear fan is on a 140mm radiator.

    Thanks everyone for the help :). For this setup I think how it is would probably give the best results because other than the rest of the case being dust filtered the 140mm fan on the rear radiator will push dust away from the radiator.
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