Just don't run it constantly at 100% and it will be fine. But why do you need it to always run at 75%? I have my 660 set to 40% fan speed until it gets decently warm, then it never goes above 59% fan speed. That keeps it nice and cool.
now i tryed with 90% 😛 and it goes down to 52c can it destroy m gpu or gpu fan ?
62C is not hot for a GPU. Set afterburner up so it does 45% fanspeed until the GPU hits 50C, then have it jump to 55% speed. Then have the speed evenly rise to 75% when the GPU hits 65C. That should keep things cool without creating alot of noise. As long as it stays under 70C you have nothing to be even slightly worried about.