CPU Air Exhaust vs. Case Pressure

[Peepnbrick]

As implied by the title, I have a bit of a toss-up. I'm using a pre-built desktop PC from HP and I was thinking of turning the 1 fan in the case around so that it draws air in instead of exhausting air. Doing this would create positive case pressure and reduce the amount of dust that enters the case through all of the little holes, assuming that I put a filter on the fan.

On the other hand, the exhaust fan is right next to the CPU. Right as I was about to turn the fan around, I thought, 'maybe they put the fan this way for a reason'. That reason being to get all of the hot air that the CPU generates out of the case.

Here is a picture of the space in case it helps inform:

Spoiler

So, I ask of you, the wonderful people of Tom's, for your opinion on which is more important: exhausting the heat generated by the CPU, or having positive case pressure and minimizing dust intake?

(I fully recognize that buying a new case would be the easiest solution, but I just made a large purchase, and want to have the optimal cooling solution while spending the least amount of money)

 

[tiny voices]

Just leave the exhaust fan. It will get rid of heat. Just clean the dust every 6 months with compressed air. Simple.

 

[ttcboy]

In my opinion, leave the fan in exhaust position because CPU cooler draw air from top and blow to the bottom and that fan helps blow the hot air out of the case.

If u turn the case fan around and pull the air in from outside, the air flow from it and CPU cooler will collide and hence will create the vortex. It will not only make ur CPU hotter but also increase overall case temperature coz u r disturbing the air flow.

If you want to minimize the dust inside the case, just buy the thin air filter from hardware store and cover it up around the air inlets.

If you want to read more about the air flow, here's a good article. http://www.tomshardware.com/reviews/cooling-airflow-heatsink,3053.html