With all case fans there lies one hidden problem; there is a dead spot of slower moving air under the center of the motor. This causes the fan not to output an exact "wall" of air moving at the same speed. This is quite obviously a problem considering that the hottest part of your CPU is in the centre, where the least amount of moving air is. CoolerMaster has solved this problem with their Dual Storm fan. The fan's workings closely represent that of a turbine. One fan inputs air which gets compressed in the middle, then the second fan outputs the air. This results in a stronger and more even flow of air which provides better cooling capability.