Better to have the power supply at the top of the case or just right above the motherboard?

[Imaginer]

In terms of cooling. Sure the power supply has the fan above the motherboard for the intake from the cpu but what if you already setting up a 120mm fan exhaust for the cpu?

 

[utopia]

the PS will produce heat, so on top will work better

 

[Ulysses]

Right. In the Northern Hemisphere heat rises.