Hot air rises so you want the fans at the top of the case to draw out the hot air. The side fans are used to intake cool air for the GPU. Bottom fans intake cool air from under the case. Check temps after adding the 2 top fans. Adding more fans than needed will cause more noise and disturb the air flow and maybe not cooling as well. Two big advantage to using a Corsair water CPU cooler are the CPU heat is carried directly out of the case by the radiator and rear exhaust fan and the air flow is smoother without the the heatsink and fan of an air CPU cooler.