It all depends on the motor. Of course, the number of blades does matter for quick cooling solutions. At the same time, the design of the fan also matters here. The engineers have checked all possible designs for a particular fan and set the blade. There are designs which are unsuitable for a four-blade system at the same time, there are designs that are best suited for the 3 blade systems. It is the overall design that matters. At the same time, the weight of the fan may slightly be on the higher side with the four-blade fans but not so high that it cannot be carried at all. The noise factor with 4 blade fans is to be considered; yes at times 3 blade fans are less noisy when compared to the 4 blade ones.