Currently I have one intake fan on the front and side (blowing on the video and pci cards) of my case, and one outake fan on the back plus the powersupply fan. I would like to put another fan on the inside of my case without, a blow hole, to blow on my cpu. Will this cause a temputure problem since air from inside the case is being blown on the cpu, instead of fresh air from outside. I don't want to put another blow hole for the cpu fan because then i would have 3 fans blowing air in(front, side, cpu side} and only 2 blowing out(power supply fan, back fan). Any thoughts.
2 in and 2 out is fine. 3 in and 2 out is fine as well, in fact having more in than out will likely help prevent dust from collecting in your USB ports, floppy drive, etc. But it's also OK to put a fan inside blowing on the CPU cooler, just as long as it's blowing in the same direction as airflow from the other fans (front to back most likely).
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I always thought 1 or 2 intake fans and two exhaust fans was the best for air circulation. Adding more fans from the side or inside might create turbulence inside the case. This may make the air flow to be worse than good. I would just stick with the basic, air flow from the front and air flow out from the back. If you computer does not run hot or computer is stable than I would not add additional inside fan.