Is there any advantage to having a psu on the bottom of your case?

Ninja Please! · 14 Apr 2009 at 01:23

Hey mates,
I have noticed a lot of high end cases putting the psu spot on the bottom. I have to ask, since heat rises, wouldn't the best place for it be at the top of the case or does somehow it defy the laws of physics to actually dissapate heat better at the bottom?

LukeTW · 14 Apr 2009 at 01:53

Its many for cable managment i think.

FaceplantSi · 14 Apr 2009 at 02:10

As you've said it's cooler at the bottom of the case and since the PSU fan is an exhaust it's sending it's hot air straight out the back and only drawing cooler air through itself.

If you look at cases like the Silverstone FT01 Fortress, it has a filtered vent underneath where the PSU goes and high case feet. This is to enable you to mount the PSU so that the fan is underneath drawing in cool air from outside the case and exhausting out the back as usual - hence it's on it's own independant airflow circuit from the rest of the case.

One thing to watch out for tho is that when you bottom mount a PSU there can be a problem with the mobo power cables not being long enough to reach their respective connectors on the mobo - particularly the 8pin one. A lot of people will buy extensions for the 8pin and 20/24pin cables so that cables can be routed behind the mobo and hence cable mgmt is easier and everything is that much tidier.

EsaT · 14 Apr 2009 at 09:13

Better question would be other way: Is there any reason for PSU to be on top?
1. It's very lousy "exhaust fan" because of high internal airflow impedance.
> More noise per exhausted air.
2. It itself needs cooling, not warming up.
> Higher stress on components
> Lower reliability or further more noise because of still higher fan speed.

Maybe all of you might not remember that when PSU was put on top to work as case exhaust graphics card had barely heard about such weird thing as heatsink and CPUs had maybe even huge ~50x50x10mm heatsink with equally huge fan.

freddie64 · 14 Apr 2009 at 10:01

Only reason its better at the bottom for me is, when i pick the case up to move it to my work bench (PC kept under desk), so it is not top heavy.

ian|Squared² · 14 Apr 2009 at 10:10

In lighter cases, having a bulky PSU at the top of the case can make it unbalanced and a bit top heavy.
Putting it at the bottom is better for its cooling, and gives the case some weight in the bottom improoving stability (if its a a light aluminium case)

Ninja Please! · 14 Apr 2009 at 13:32

Thanks for the tips. I will keep in mind when I look for my next case.

Guardsmon · 14 Apr 2009 at 13:49

Think FacePlantSi said the most sensible and useful answers.
If only lian li put the PSU at the bottom of the PC7+, You could put the 2x 3.5" external bays at the bottom as well. hard drives mounted sideways and bam you have a wonderful case. They might have to call it a PC10 though now as they have some many other variants.