Help tuning my GPU with ASUS GPU Tweak

I have an ASUS GTX 650 ti and I'd like to know how is the GPU Tweak used. As of yet, I've only used it to augment the intensity of fans when I start gaming. But I'd like to know what does each option do and how far can I augment each option before I mess up with my GPU.

Watch this:

http://youtu.be/zkJez9Og7fc