My case came with 2 fans: One in the side and one in the top. The side fan was set up to blow air out of the case? That didn't make sense to me at all so I reversed it to blow air into the case and right into the cpu. The top flows out so it's a one direction flow. Everything was fine but I just cleaned a whole lot of dust off my cpu heatsink and that lowered my temp 5 degrees lol. My question is should I have left the fan the way it was? That was a lot of dust in there.