Install nTune and accept the end user agreement. Then you have fan control and GPU clocks under "Adjust GPU settings". I had to install nTune and accept the end user agreement to get Riva Tuner to allow me to OC under Vista x64 for some reason. Options were gray and locked until then.
If you game with headphones on high fan speed shouldn't bother you. I run 75% when I game because I have a medium high OC. I use the headphones so it doesn't matter to me.
It should look like below after you accept the agreement-