Fan placement

hi guys


I have the cooler master N400 and i want to know what is the most optimum way to place fans. Is inflow more important or out flow. my mother board has 3 chassis fan ports so i can only add 3 fans. so should i have to inflow in front and one out flow in back or two out flow in back and one in flow in front .


plus which fans are better high air flow or high static pressure


thanks in advance

I kind of like that case. I would say two in the front , one in the back. I like to put a sp in the front if i think its a little restricted. With that case, it may not be necessary. Its pretty open. Af fans would be fine unless you fill the front full of drives. Two intakes one exhaust .


for the case net air displacement is what counts,

you can do that with

  • positive pressure (more intake than exhaust)
  • negative pressure (more exhaust than intake)
  • balanced (intake = exhaust)

there really isn't a "best" way to do it, you should experiment with your gear and find out what works best, for your specific gear.

my experience:

  • positive pressure with dust-filtered intake tends to be the best solution for pc's in dusty environments.
  • negative pressure tends to be the best solution if a case is crammed but negative pressure also tends to suck in dust through secondary holes. All laptops use negative pressure.
  • balanced tends to deliver the lowest temperatures for big cases with good airflow

For case fans you want high air flow fans (assuming that the air-path isn't heavily obstructed)

For fans on coolers (cpu & gpu) you want high static pressure

For your case & 3 fan restriction, i concur with Freakmaker:

  • Intake: 1 Front 1Side (graphicscard)
  • Exhaust: 1 Back
  • block off with tape and cardboard all other fan opening except for the top opening

-> experiment: set up a configuration and run a few benchmarks, try at least 3 configurations and pick the one that nets the lowest temperatures.

Note i would ad a fourth fan for your case to get a balanced fan configuration: i often clip the connectors from a power-supply-cable and fan cable and solder them together, if i don't have enough fan ports on a mainboard.

In reality you really want both supply and exhaust to be the same flow rate. Its all about heat transfer so having a positive or negative pressure wont make a difference but add more load onto your fans making them less efficient. Unless its in a vacuum of 500 microns then ya gonna have issues. (joke)

Also are you using any water cooling systems. If so make sure your radiator is forced draft facing into the chassis. So many people get this one wrong and it can make allot of difference by having the Fan around the other way. Last thing you want on that radiator is the internal heat of your case. You want nice fresh air going past that radiator not hot air.

A simple nice setup would be to have a front chassis intake supply fan for your HDD. A rear supply fan blowing on your radiator/heat sink fan, Your PSU is already supplying external air. And if its possible a large top mounted exhaust fan.

As to your GPU coolers there's nothing you can really do unless you know how to revers the polarity of the fans and have them inducting outside air as well. don't know why Nvidia and AMD still have them blowing hot internal air instead of cool fresh air. Out side air is always going to be cooler then inside the chassis so have no idea why? 

If you really wanna get technical you can use the basic heat transfer capacity equation Q= AUTd



Thanks guys

I have 4 fan so will try to make fourth one work to get the balance,though if that  does not work then I will use two in Ndone out. 


No,I don't have any water cooling and the PSU is in bottom so it is independent and not providing any airflow in or ouT