Do you want to fry your 8790?
Not meaning to to facetious but why do you want to control the speed of your fan? I know in a quiet environment the normal fan speed can be annoying but to lower it more if that is what you are wanting to do, you do realise that applications running in the background, some applications can demand a lot of work out of the CPU, making it work hard and generate a lot of heat. A lower fan speed to me means less cooling power and I'm sure over time you'll damage the CPU. If it ain't bust, don't fix it. One way to ensure you have a really dead-quiet laptop fan is to switch off the laptop
<-- your CPU soon!