Originally Posted by Himo5
Here's one I'm in the process of setting up.
In my experience a top intake is never good. The hot air rising will just get pushed back down into the system, and with the way the other fans are setup it could just create a vortex in the middle of the system and the hot air will have difficulty getting expelled. Although every case and fan is a little different, the basics are bottom front intake to top rear exhaust.
Now with that said I had an interesting situation recently on my current build, has 3x120mm intake in front and 3x120mm exhaust in rear and top, and the case has tons of openings everywhere. Because the fans are not all the same model I ended up having negative pressure and was literally getting a layer of dust on the components within 48 hours, (kids, pets, carpet, common walk way, dust everywhere!), I switched the rear to an intake to change it to positive pressure, it increased my overall system temp by 1C but viola!, no more dust in the case. Just goes to show that even with basic air flow rules, every case and fan is different.
EDIT: Forgot to add that yes usually negative pressure is overall better for cooling but you have the whole dust thing to worry about. Like my situation above, with only 1C difference in temp, the positive pressure outweighed it.Edited by Radnad - 3/29/15 at 8:45am