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Positive vs. Negative Airflow

post #1 of 43
Thread Starter 
This is just a debate forum i guess and too see what more people have.

Postive Airflow.
Postive airflow is having more intake fans then exhaust fans, this isn't real bad but then if you dont have enough exhaust fans air will be trapped inside your case then not having a real good airflow.

Negative Airflow.
Negative airflow is the opposite of postive airflow its having more exhaust fans then intake fans, this is good because its always taking new air into the case, but then you have more dust because the intake is mostly coming from gaps in the case and then causing trapped air.

The best airflow is probably a balanced airflow with the same amount of intake pressure as exhaust pressure!

Anyway this is just a debate between which is better!
post #2 of 43
I believe an equilibrium of the two is the most effective. But if I had to, I would chose multiple intake over lesser exhaust.
    
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post #3 of 43
Isn't it more important to have a positive/negative pressure debate rather than airflow?

you could have 2 fans exhaust with higher static pressure than 3 fans intake.
or even 2 fans intake with 51cfm and 3 fans exhaust with 28cfm.

Just a thought...

oh and to answer your question:

3 intake over rads, 1 large exhaust in top of case for me. smile.gif
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post #4 of 43
I'd rather put pins in my eyes than have an airflow debate.

It literally depends on your ambient temperatures... if your ambient is higher, you want to be sucking air out of the case, if you have a lower ambient, you want to be sucking air into the case....
    
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post #5 of 43
LOLWUT?
Positive airflow = air flowing in a positive direction, on some unknown axis (define it?)
I guess you mean positive pressure? would make a lot more sense that way..
    
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post #6 of 43
IMO Positive is better its good to have a little pressure to get those deeps parts cooled wink.gif

but equal is good 2 but i would never go negative unless i have really good intake
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post #7 of 43
I prefer positive pressure with air filters. If you have a positive pressure case all of the air inside the case passed through an air filter and air is being pushed out of any cracks in the case preventing dust from getting inside. If you have a negative pressure case then air is being sucked in any cracks in the case and it doesn't matter if you have air filters because dust will still get inside.

My Silverstone FT02 case has extreme positive pressure with 3X 180mm fans as intake and only 1 slow 120mm fan as exhaust. It is the best air cooling case that I know of. Even with the fans on low I can feel air shooting out of the gaps in between my 5.25 inch drive bay covers.
    
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post #8 of 43
Thread Starter 
Sorry i mean positive vs. negative pressure!
post #9 of 43
I believe in positive pressure, and have tried a lot of different configurations in the past decade.

Currently I'm using 11 intake fans (7x9mm and 4x120mm), and 2x120mm exhaust fans. The reason behind this is much less dust, and turbulence in the case doesn't hurt with getting into crevices to help cool small, hard-to-reach parts. I have enough pressure in my case that, if all fans are turned up completely, I can actually stick my hand in front of a 3.5" bay cover, and feel the air shooting out of it, enough to cool off sweat in a gaming scenario, or even blow on my face and keep it cool. I haven't had to worry about dust yet, since it's all filtered.

I don't believe ambient temperature has much to do with the effects of negative or positive pressure, although it will have an effect on all temperatures. At the least, a balanced, or positively pressurized case will be right around ambient from what I've seen. High flow negative systems will be about the same, but dust will accumulate very quickly (2 to 3 days in my previous cases). I don't really find it to be quieter, either.

For me, I'll stick with positive pressure.
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post #10 of 43
Intake is better than exhaust. Pushing hot air out is easier than pulling hot air out.
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