Lordbob75 said:
GeneO said:
Lordbob75 said:
Heat rises!

The front and bottom fans should be intakes, with the top and rear fans being outtakes.
It doesn't really matter if heat rises when you have air flowing through the case. Convection gets broken up by the flow of air through the case.

I think that maybe historically having fans on top be exhaust fans is because PSU used to be mounted on top, sucking air in from the top of the case and blowing it out the back. Putting an intake fan on top would not be effective in that configuration because it feed the PSU fan.
Correct. The main point is that you want good airflow, but that's been the standard for a while. Even if the heat rising thing isn't hugely important, I could definitely see it making at least a small difference.
I believe it is completely negligable. Hot air rises due to buoyancy (hot air is less dense than cold) and airflow and turbulence mixing hotter and cooler air inside the case will not let any density gradient form, which is necessary for this to happen. You need a static environment for that if you are passively cooling your coputer without fans, venting at the top may be beneficial.