Yes, the fan size technically matters. The bigger the size of a fan, the simpler it will be for moving a greater volume of air and (with the right placement) the more it will offer along with the heatsink to cool a space. However, it is in no way, the only factor to consider. The intensity of the fan in cycles every moment; the average flow generated; and even the pressure generated, all are factors that add to the convenience of a fan in our equipment.