What ham is there in cooling the CPU by removing the CPU fan and using a small external fan, such as a small personal desk fan to blow air directly onto the heat sink from the case vent that is directly in front of the CPU? Rather than trouble to replace an original CPU fan, I am thinking of just removing it and using the above arrangement, maybe with a dust screen over the case vent. It will take a bit of space and make more of a whir, but I cannot foresee any other problem. Am I neglecting something?