Originally Posted by narcopletic pc
it is happening, per the new PC case layouts were seeing with the PSU on the floor of the case sucking straight from the outside & venting it back out the rear..
but the old case design has worked perfectly for years with the PSU at the top, thats why a 140mm fan was added to newer PSUs to help remove hot air from the case
but its not really an issue, your PSU will never die from the extra heat of your components...
it is on the other hand possible to create a ''dead spot'' where the PSU fan cannot extract due to chassis fan configs, but each case is different so its something you would have to test.
move your chassis fans to different locations each time holding your hand by the PSU exhaust, see if the flow changes at all. (i doubt it will)
i always try to put a ''positive'' pressure inside the case (more intake than exhaust), so air cant be sucked in through cracks & drive bays, thus lowering dust coverage
but a PSU can get very hot so i wouldnt worry too much....