Using the H80i GT with the CPU at its stock settings presents us with an interesting set of results. By having the fans set at default (PWM) there is approximately 10-11C in difference when the fans are set to maximum speed. H80i GT competes with all of the flagship air CPU coolers when the fan speeds are 2000RPM+ but obviously noise is something that has to be compromised on. We suggest the sweet spot is around 1500-1800RPM for a good balance of performance and tolerable noise.
Corsair H80i GT Fan Speed: MAX = 2500RPM / PWM = 1200RPM