Tiny Cooling Fan what is a good strategy?

"Tiny Cooling Fan" what is a good strategy? Some buyers always think better cooling fins, in fact, this is a wrong idea, the big advantage is that the fan blades long, large cooling area, so the larger air flow. However, if designed properly, "Tiny Cooling Fan" cooling capacity may not be as good a small fan. Finally, look at the cooling fan blades, the same fan if other parts remain the same, only the leaf blade from five to seven blades, wind changes may not add much. But on "Tiny Cooling Fan" in terms of speed, seven blades of the fan speed will be lower than five (under the same ventilation rate), the opposite if seven fan blades, bearing wear, oil spills less , the longer the life of the fan.