Check the temps of your CPU/GPU and decide what level you need to run your fans at, I would guess that if you have good air flow through your case you won't need to run on high the majority of the time.
http://www.techpowerup.com/realtemp/ is a good utility for watching your CPU temps
http://www.techpowerup.com/gpuz/ is good for your GPU
Run some stress tests and watch your temps to decide.