As covered earlier on slide #12, using multiple fans will lead to an increase in sound level. Careful consideration must be made to how many fans to use so that sufficient cooling is provided to the chassis. A preference would be to use as large of a fan that can fit into the chassis, since it requires fewer large fans to provide the same amount of cooling. Another disadvantage of using smaller fans is that they need to rotate at higher speeds to provide the same airflow as a larger fan, and higher fan speeds result in higher noise.