View Full Version : negative pressure case

29-12-2011, 12:11 PM
I have a cm storm enforcer case 2x200mm front intake top exhaust
my tmpin1 in hw monitor is 50 -58
I want to put a 120mm upgrade fan in rear making my case negative pressure
current cfm 110 front 110 top rear 45cfm
I am putting a 103 cfm in rear

my intake fan is filtered
what do you think?:happybday

29-12-2011, 12:59 PM
I think pressure has nothing to do with it and airflow everything to do with it.

29-12-2011, 01:05 PM
I've never been a big fan of having the PSU at the bottom of the case, coz the heat from it rises through everything else.

That said the large top exhaust fan quite possibly helps the actual airflow, though I'm not convinced the warm air from the PSU is good to have rushing over everything.

Anyways I'm with pctek, the debate over the pressure, doesn't interest me. Flow in from the front (ideally) and out through the back or top. Simple :)

29-12-2011, 06:49 PM
I never learn, type a novel, push escape, make an anguished noise as it all dissappears....

Anyway, short version - extractor fan good, cools whole system. Intake fan mediocre cools whatever is directly in the path of the fans and that's all.

Positive pressure + filters = dust control
Negative pressure = better cooling at the expense of more difficult dust control.

Use negative and clean the PC occasionally. Adding the Fan should drop system temps but if they arn't too high why bother. More Fans = more noise.

29-12-2011, 09:59 PM
Aaah don't you hate when that happens :(

30-12-2011, 11:08 AM
Incidentally Chill, The PSU tends to draw in cool air through the bottom and vent it out the rear, no air gets into the case at all to heat anything, maybe the metal warms a bit but it's minor.

On the other hand while a top mounted PSU can help slightly with airflow it means it has to do it's own cooling with pre-warmed case air making the PSU run hotter.
I prefer it at the bottom myself :)

Of course some crappy old PC cases relied on the PSU as the only airflow. I guess PC's just generated less heat back then.

30-12-2011, 11:40 AM
Interesting, I should look in to that a bit more then :)