Why isn't the push style ventilation common?

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pwnt

Weaksauce
Joined
Jul 31, 2007
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Most computer cooling is setup in negative pressure, so the air is being drawn out and surrounding air is pulled into the case. The problem with this setup is that you can filter every entry point and dust accumulates everywhere, including the bezels of drives.

In a push style setup with one air intake, you only have to filter the sole intake to keep the dust from getting inside. Does this not work well for computers?
 
Most PCs use a push-pull setup... since power supplies always exhaust, and some videocards do, you need to balance that flow with intake fan(s).

Realistically though it makes more of a difference with cooling to draw the warm air out than to add cool air to the case.
 
The problem with intake only PC fan setup is that dead pockets of hot air can form inside the PC case. You need some type of exhaust to keep airflow circulating throughout the case.
 
What about making sure inside the case is always maintained under positive pressure, then opening up a path where cooling is needed (such as PSU, video card) and using recirculation cooling for areas like CPU?

On my computer, I have an intake filter on the CPU heatsink and the filter catches a lot of dust and traps lints, but the fan still manage to accumulate fine dust.
 
the cooling setups are probably flowing OK inside the case, but how is airflow outside of it. If a case sits under a desk, then the majority of exhaust (hot) airflow builds up behind & near the top of the case, has no escape path, and is hot-recirculated back into the case.
the only way to avoid this is with 8" + of space behind the case in all directions with adequate air drafts in the room ....
anybody have an infrared heat vision camera :)
 
You could use a powerful blower type fan along the top side of a side panel and force the air down.

Car radiator is setup so that hot water goes in from the top, then out the bottom...
 
mainly do too the poor design of PC's from a heat handling perspective.
BX which never caught on could get the same level of cooling with 2/3 the airflow.
The basic layout hasnt changed since the 8086 days and 100X the heat is being pumped into the case in some setups. (yea yea at vs atx dont count)
less than 10W vs 1000W
 
It just old case design where OCing was not the target consumer. Thus a single 80mm fan down in front that limited air intake because the case manufacture was selling 10,000 cases for office drone machines to every one sold to an OCer.

Of course now we see cases made/marketed for OCing with at least a 120mm fan intake and side vents for the CPU etc. so things have changed. However OCers are still a very minor market and still most cases are crappy for airflow. So that is the why. It easily can be gotten around now by carefully choosing your case. I personally agree with your basic idea, I want more air in than out mainly to prevent any chance of heat buildup but the dust thing is a very valid concern too. I will not buy a case that does not have at least a 120mm fan in front (and try to avoid the ones with a drive cage that limits the front fan to the slim ones) AND a 120mm in back AND a side CPU vent unless I intend to water-cool the machine.

Case manuf still sell 10,000 cases to one so there are still plenty of crappy (for our purposes) cases out there and Stormy1 has the history correct. The evolution of the design of cases for high performace has been slow and painful with only a few exceptions.
 
The category covers overclocking as well as cooling. I don't plan on overclocking, but it would be nice to not have any dust accumulate in optical drives and the only maintenance required is cleaning the intake filter.
 
Check out this link:

http://icrontic.com/articles/pc_airflow_heat_cooling_guide

The article is a bit old but has some very valid results.

One of the summary items is:
"A single rear exhaust fan produces the best results overall."

I tested this theory on my system and I found it to be true. Excluding internal fans, I have one, 120cm, 110cfm at the rear + std PSU fan and it cools much better than if I have any intake fans at all.

Saying that, every case is different and you should test it yourself and see what works best for you.

And yes, lots of negative pressure is good for cooling but quite bad for dust (at least in my house).
 
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