it doesn;t matter how many fans you have or how many are blowing in. it all depends on AIRFLOW, hence the name. You have to make sure there is no negative or positive air pressure in your case. Generally, you want two intake fans and one outtake fan. the PSU will take the rest of the hot air. If you have a blowhole, great, but it will create a negative pressure if you only have two intake. Side fans? I don't like them. Disturbs the natural flow of air from bottom front to top back. instead, get a slot fan and put it right on top of where the GPU HSF exhausts