Tiny Cooling Fan how to choose?

Special designed various "Tiny Cooling Fan" is nothing more than the blades and frame to enhance the performance of a particular or a few aspects of the fans, but are often unable to take into account a specially designed all aspects of performance, so that the user can actually use need to select one of a particular product:
1. "Tiny Cooling Fan" has no special requirements, just want to be able to enhance the effectiveness of the traditional axial fan basis, reduce noise. AVC "Dragon hand wing" off the edge of the fan and Tt "Silent Boost" side of the inlet fan is a good choice, but only for 6cm and 8cm respectively in two sizes.
2. At the same time does not require high pressure, want to provide a greater amount of lower wind noise, Tt trefoil fan, YEN SUN external magnetic fan of TMD can be considered, the latter increases the area over the air, reducing the blind, but optional sizes also limited.
3. "Tiny Cooling Fan" with a large heat sink drag the needed amount of wind diminished fan while providing a greater pressure, do not want to or can not continue to increase the fan speed, it has to be considered with a frame or deflector multi-channel fan blades. If the central part of the heat sink is also an urgent need for airflow "care", Cooler Master's "Tornado" series turbofan is the most appropriate choice; but only 7cm and 8cm dimensions are two, and the "head" high. The choice of any of these three, have to endure a substantial increase in noise in use.