This may seem silly, but I'm having a disagreement with a friend on how to properly mount a PSU in a new system.
The PSU in question is an Antec EarthWatts 750 and the case that it needs to go into is a CoolerMaster HAF 922.
The question is which way does the fan go? Does it point downward and use the airholes at the bottom of the case? Or does it point upwards?
If the fan does have to point upwards (so that it can suck air out), then the ATX12V cable is just an inch too short to go around the back plane and attach to the motherboard, which results in a messy looking build.
12 cm fans on PSU's suck air into the PSU to cool the components, like a cpu cooler works. and the fan will face downwards, like it would in a normal case
I should have added that the PSU is bottom mounted in this case.
So if it sucks air into the PSU, and the fan is pointed to the bottom of the case, then the fan will be sucking in all the dust bunnies? If I flip the PSU upside down so that the fan points to the CPU, then the air that will be sucking is warm (but dust bunny free air) from inside the case?
So to avoid the evil dust bunnies, I should mount the fan pointint upwards, correct?
There is one exception to a psu pulling in warm air from the interior of a case and exhausting it out the rear of the case. If there is sufficient case ventilation, air flow, and cooling, then the psu can be mounted fan side down over an opening in the bottom of the case. The theory is that the psu can pull in fresh air and cool itself. As an example, the Coolermaster HAF 932 has outstanding ventilation, air flow, and cooling, so I installed the psu fan side down. Cooling results for the cpu and gpu were still excellent. On the other hand there may be a case with poor ventilation, air flow, and cooling that could use the extra cooling a power supply can provide. It just depends.
About those dust bunnies - I never put a pc on the floor. A few years ago I made a nice black and chrome pc stand with casters. I got the parts at a local hardware store.
Fan down pulling colder outside air is a nice option to have; most cases require you to cut a hole to do it. Also you want to add taller feet for more clearance.
That HAF 922 has a huge front bottom fan pushing air in. I doubt the PSU orientation will make any difference to the GPU or CPU temps in that case. If that case is on the floor, the front fan is going to suck in dust bunnies.