I had the same issue with my Apevia x-dreamer 4 case, but I ended up removing the side-fan, because it was definitely better to have 2 fans on the CPU cooler in my case. If you have fans pushing a lot of air from the outside to the inside of the case, you could always have it push the air out to create an air flow. The H75 is, in my opinion, too thin, mostly if you plan to overclock your system.