Originally Posted by Phelan
One thing to note, and something I've noticed from personal experience, is that even with 2 standard low-RPM 200mm fans up top, is that 2 fans can push more CFM than the top mesh will allow through
. You can see this for yourself if you pull the front case bezel with both top fans running. You'll feel a significant amount of air coming through the little rectangular hole in the front of the top case bezel.
That's somewhere between wrong and not phrased well. It's misleading either way.
Even if you had only one small 80mm fan up top, you'd still feel some air exit that little hole.
The top mesh does restrict airflow somewhat. You're going to get backpressure behind the mesh, but it does not act like some kind of a fixed level limiting valve. (at least at flow rates we're working with).
The backpressure is to be expected. There is less cross sectional area of combined mesh holes than there is of swept area by the fan blades. Additionally, the small size of the mesh holes offers more resistance to airflow than the same area of larger holes.
Physics is physics . . . If you give the air another path out, (taking off the front panel) then you have to expect air to come out there. Air flow will divide by the number of paths, and quantify inversely by the resistance.
With the more powerful fans, you're pushing more air up behind the mesh and consequently more pressure to push more air thru the mesh.
It is not a linear relationship, but more fan is going to translate to more air flow thru the mesh and also thru a top mounted rad which is a good thing for cooling.
DarleneEdited by IT Diva - 9/29/12 at 4:32am