My casing has a 120 mm fan in front for intake and 120mm fan at the back for exhaust. I am planing to buy a new power suply with those 120mm sillent fan. So my question is if the air flow in a pc is not equal will it be a problem? Meaning if the casing is taking in more air than its exhausting or the other way round. So given a choice which is better? Equal air flow, more intake or more exhaust.