3 x 120mm fans or 2 x 140mm fans?

[Archer3545]

On my case that I am using for my current PC I wan't to get the most optimal airflow and when consulting my motherboard to see what sizes it supports I found that the rear exhaust can have a 140mm and the front can have 2 140mm and that what I plan to get but I found that the top supports up to 3 120mm or 2 140mm and sound does not bother me I just want to know whats best because I know larger fans can be much more efficient so idk really know whats better

 

[knightslugger]

2x140mm gets my vote.

[dfsdfgfkjsefoiqzemnd]

The problem with those top-mounted fans is that they usually have no filter and hence are exhaust only.   The rear by default isn't filtered either, so that is exhaust only too. 

 

With 2x 140mm intake at the front and 1x 140mm exhaust at the back, you have positive pressure. 

Add a single 120mm fan in the top and you're close to neutral. 

Anything more will generate negative pressure inside the case, causing dust to be sucked in through all the openings in the rear and between the panels. 

 

 

 

Unless you are running a really big CPU and dual or triple graphics cards, 2x 140mm intake and a 140mm exhaust should be sufficient. 

I have just that fan setup in a Fractal Define R5, which has an i5-2500 and a GTX770 (not really the most power-efficient card) folding 24/7.  The temps are 2-3°C higher than when the same setup was in a HAF X with 4x 200mm and 2x 120mm fans. 

[WoodenMarker]

Smaller fans are actually more efficient when it comes to performance/size. If you really don't care about noise, 3x120mm's can deliver more performance. 

That being said, it may help to list your specs and explain what you're looking for if you're not sure what you need.