Modders-Inc checked out the Under Pressure: Parvum F1.0 VS NoiseBlocker eLoop B12.2 Static Pressure Fan Comparison A quote from the article:

It hasn't been since the last few years that the case fan has evolved from the same standard design to companies now introducing fans that serve a specific component purpose. With watercooling setups becoming more and more common among mainstream systems, it was only a matter of time before the standard case fan became obsolete and the enthusiast market demanded ?

 Under Pressure: Parvum F1.0 VS NoiseBlocker eLoop B12.2 Static Pressure Fan Comparison @ Modders-Inc