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Push-Pull and Positive Air-Pressure are Both Scams?

Tags:
  • Pull
  • Tom's Hardware
  • Air Pressure
  • pushpull
  • Push
  • Cases
  • Configuration
Last response: in Components
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Positive Air Pressure

Total: 4 votes

  • Legit
  • 75 %
  • Scam
  • 25 %
  • How the hell should I know
  • 0 %
July 9, 2014 4:36:05 PM

Push-Pull is pretty.. useless. Theoretically it shouldn't give you any better temperatures. Think about it, pulling in air that's already being pushed? The fans can only pull as much air that's being pushed by the other fans.

Same with positive air pressure... How should that give me better ambient temperatures? Wouldn't the best configuration be to have all my fans blowing fresh air in my case and have vents at the top for the hot air to escape?
Why should positive air pressure reduce dust in my case? The air (carrying dust) is passing through several components before reaching the exhaust.

I've also wondered why the standard tower case design is still around. Take a close look, its horrible for airflow/cooling. There are corners, things blocking air flow, wires, etc.

I'm not being an asshole either, I just want someone to prove me wrong so I can stop thinking about it :p 

Thanks for reading my rambling

More about : push pull positive air pressure scams

July 9, 2014 8:02:57 PM

Push-Pull is not a scam. Fans have pressure-airflow curves, they aren't always moving as much air as they could, especially with heatsinks since ramming air into the fins will result in a lot of back pressure. If you are just pushing into the fins you end up with higher pressure air between the fins. If you now have another fan on the other side pulling you can reduce the pressure differential and move the fan to a point on the curve with higher airflow since the pressure differential between each fans intake and exhaust is now reduced.

As for positive pressure vs negative pressure, there is debate as to which one gives you better cooling i don't think it makes much difference.

As for reducing dust, positive pressure is commonly used to reduce dust since you have filters on your intakes so you remove the vast majority of the dust from the air you are intentionally blowing into the case, if you have negative pressure you have a small amount of airflow from every gap and vent in the case, all of them sucking in air with dust, and with that many entry points you can no longer filter it out.

The standard tower case is just cheap and efficient, sure its not perfect, but its good enough. A couple fans on the bottom front, a couple fans on the top back, you can get a fair bit of air moving and it will blow across most of the components that need it. In all engineering applications there is a great solution, and then there is the fast, cheap, and easy solution that works well enough, a box with holes and fans slapped on it is real easy to make, a super smoothed out and contoured case would be very difficult to make and would only gain you a few C anyway, not worth the effort.
July 9, 2014 8:08:25 PM

suck in the cool blow out the hot crank up the AC to even it out
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July 9, 2014 8:17:13 PM

push pull require the fans to be quite similar so preferably the same brand and model

my fans aren't good enough for positive air pressure T.T
July 9, 2014 8:22:04 PM

With my h100i with push/pull using static pressure fans my temps are 3-5c cooler
July 9, 2014 10:07:16 PM

coolcole01 said:
With my h100i with push/pull using static pressure fans my temps are 3-5c cooler


You would really spend $40-$60 more for 3-5c less?
July 9, 2014 10:09:34 PM

hunter315 said:
Push-Pull is not a scam. Fans have pressure-airflow curves, they aren't always moving as much air as they could, especially with heatsinks since ramming air into the fins will result in a lot of back pressure. If you are just pushing into the fins you end up with higher pressure air between the fins. If you now have another fan on the other side pulling you can reduce the pressure differential and move the fan to a point on the curve with higher airflow since the pressure differential between each fans intake and exhaust is now reduced.

As for positive pressure vs negative pressure, there is debate as to which one gives you better cooling i don't think it makes much difference.

As for reducing dust, positive pressure is commonly used to reduce dust since you have filters on your intakes so you remove the vast majority of the dust from the air you are intentionally blowing into the case, if you have negative pressure you have a small amount of airflow from every gap and vent in the case, all of them sucking in air with dust, and with that many entry points you can no longer filter it out.

The standard tower case is just cheap and efficient, sure its not perfect, but its good enough. A couple fans on the bottom front, a couple fans on the top back, you can get a fair bit of air moving and it will blow across most of the components that need it. In all engineering applications there is a great solution, and then there is the fast, cheap, and easy solution that works well enough, a box with holes and fans slapped on it is real easy to make, a super smoothed out and contoured case would be very difficult to make and would only gain you a few C anyway, not worth the effort.


My god you have answered all of my concerns. Thank you very much for taking the time to respond, I have a greater understanding now.
July 9, 2014 10:10:08 PM

I got my extra 2 fans for 14.99 so yes
July 9, 2014 10:15:24 PM

coolcole01 said:
I got my extra 2 fans for 14.99 so yes


That's a little more practical. Speaking from experience I've seen friends spend up to $80 on 2 sets of pressure optimized Noctua fans for only a 3-5 degree reduction
July 9, 2014 10:47:40 PM

You gotta do your due diligence if you want a great deal
July 10, 2014 2:45:02 PM

Noctua fans aren't cheap, they aren't supposed to be. Noctua sells their fans at a premium and if you wanted a decent fan you wouldn't get a Noctua, you'd get a cheaper one, if you want a great quite fan then you spring for the Noctua. Just because some higher end fans are expensive doesn't mean all are. If you spend enough time looking you can find a great deal on anything.

coolcole01, what were your temps with the H100i before you set up the push pull? It usually has a pretty low deltaT so 3-5C at load is probably a rather large percentage change, Frostytech was only seeing 10C above ambient @150W so a drop of 3 would be a 30% improvement in cooling performance! Thats pretty damn good for a $15 investment
July 10, 2014 7:16:07 PM

on average my idle was about 35c without push/pull with them 29-31c running prime was getting 57c now it usually hovers around 50c leaves me even more room for overclock
!