On a normal 80mm case fan, the central hub (Containing the motor) accounts for approximately 16%-20% of the total surface area of the fan. Now, this doesn't tend to pose any problems with an intake/exhaust fan, but when mounted directly on top of a cpu heatsink it can create a dead zone. In real terms, this means that you are not getting the maximum potential airflow. Combating this requires mounting the fan away from the the top of the heatsink, using a duct to guide the air. This is exactly what this new product is supposed to do...
