PSU Position

[Enneikay]

So, I didn't build this PC myself and the psu is mounted at the bottom with the fan pointing up. 

I'm about to buy (most likely) an XFX Pro XXX 650W, should I put it with the fan pointing down? I have a CoolerMaster HAF-912.

 

In case you need to know, PC right now is on top of my desk, but my floor is wooden with no carpet.

[Oshino Shinobu]

If you have a dust filter under the PSU, then I'd say yes. It will be sucking in fresh air then. 

[Fred Castellum]

It depends on the airflow of your case. If your components are set to exhaust air upwards then you might want to have the fan facing the bottom of the case. 

[acidydragon]

In most cases, down is preferred, but it can also depend on the other fans in your case, and if you have a filter on your case.

[Probenja]

If there is enough ventilation put the fan facing down, if there is not enough ventilation or there is too much dust put it facing up.

[TheDigitalRealm]

Depends on your individual situation. I, for example run my Power supply fan side up because I have 4 intake fans and only 3 in exhaust running at a lower RPM, so to get my air pressure SLIGHTLY positive I run fan side up.

[Enneikay]

I checked google and most images (aka every single one except one) of builds with my case uses psu pointing down. So I guess I'll put the new one facing down. I'll check how everything is set once I buy my gpu and the new psu. Thanks

[Faa]

It doesnt matter that much, I would face the fan upwards to help exhausting heat out of your case, theyre efficient enough so its pretty much safe to do.

[Keel]

Even though my case has a dust filter on the bottom, I still have mine with the fan sucking air from the inside of the case but only due to it sitting right next to an open window, that just happens to open from the bottom. That only sometimes has a fly screen to block leaves and insects. Because cats.