AIO fan orientation?

[Legend]

I have a Nepton 240M which I'm mounting to the front of a Cooltek W2 as intake. Does it matter which side of the rad the fans go, i.e closer to the outside, or more visible on the inside? Which is optimal?

 

[SamyBoy13]

If you have a fan that makes a seal with radiator (the square ones) there should be no real difference maybe 1-2 Celsius degree which is reading error more likely. Many people although prefer to put a fan to push air either to the case or out pushing air though the fins of radiator to the case or out.