Psu fan upgrade/orientation

Man of Honour
Joined
12 Jul 2005
Posts
20,513
Location
Aberlour, NE Scotland
The idea of the psu fan pushing (intake for the psu casing) is that it forces air over the heatsinks and other components. If you turn it around you won't get the same level of cooling and could possibly increase the chances of psu failure. Manufacturers have them that way around for a reason plus they know what they are doing so leave it alone.
 
Soldato
Joined
7 Mar 2013
Posts
3,322
Location
Caistor
According to a Seasonic Rep from a separate forum, if you're using Hybrid mode (i.e. semi-fanless) it's actually recommended to have the grill facing upward to let the positive pressure inside the case push air through the PSU, whereas if you're using active mode (i.e. fan always on) or if the case has a enclosed bottom basement then it's better to have the grill facing downwards so that it can pull fresh air to actively cool itself.
 
Soldato
Joined
12 Feb 2009
Posts
4,324
According to a Seasonic Rep from a separate forum, if you're using Hybrid mode (i.e. semi-fanless) it's actually recommended to have the grill facing upward to let the positive pressure inside the case push air through the PSU, whereas if you're using active mode (i.e. fan always on) or if the case has a enclosed bottom basement then it's better to have the grill facing downwards so that it can pull fresh air to actively cool itself.

From that I can tell the seasonic rep, has limited knowledge on air pressure. If there was enough air pressure to counter thermal dynamics (unlikely) it would work just as well if not better with the fan face down, as long as there is an air intake within the case as it would be working with thermal dynamics, not against it. This is basic secondary school level science. :/

A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.

This topic is a pet peeve for me. >_< If I can be arsed at some point I may produce a diagram to show this more clearly, cause it seems people need to be educated.
 
Soldato
Joined
7 Mar 2013
Posts
3,322
Location
Caistor
From that I can tell the seasonic rep, has limited knowledge on air pressure. If there was enough air pressure to counter thermal dynamics (unlikely) it would work just as well if not better with the fan face down, as long as there is an air intake within the case as it would be working with thermal dynamics, not against it. This is basic secondary school level science. :/

A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.

This topic is a pet peeve for me. >_< If I can be arsed at some point I may produce a diagram to show this more clearly, cause it seems people need to be educated.


Not entirely scientific but it does demonstrate that it's more situational than secondary school level scientific theory.

Also, per your description of the micro-climate of the PSU, if the fan is facing downwards, assuming there is no external heat source, has a more resistance to the air current than when with the fan facing upward since as hot air raises, a close air vent in the path of the raising air will produce resistance compared to an open air vent.
 
Soldato
Joined
6 Jun 2008
Posts
11,618
Location
Finland
If needing to ask which way PSUs fan blows air it's best to keep fingers far from PSU's insides.


A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.
Convective temperature difference based cooling works best with as little as possible obstacles in path of warm air.
And air having to squeeze through between PSUs components and then rear mesh is definitely more restrictive than warm air being able to rise straight up.
Components farthest from rear mesh might have problems in getting airflow.

Again with fan running and forced airflow there just shouldn't be any significant differences for as long as there's no restrictions for fan's intake airflow.
Though with PSU on bottom having fan upwards is risk of screw falling into PSU.
Even if there's no power and it doesn't cause short circuit that screw might not come out so easily.
 
Soldato
Joined
22 Mar 2014
Posts
3,956
I always have mine facing down for dust reasons, the bottom has dust filters but the top of my case doesn't which some dust gets through even with my magnetic modded filters covering it.
 
Back
Top Bottom