Downclock GPU to prevent excessive heating

Hi to all,

I am looking for a solution to set an arbitrary frequency threshold on my "AMD Radeon HD 6750M 1024 MB". This in order to prevent the excessive heating of the GPU self. However, I found a "bad" solution: I use a programar (gfxCardStatus) to impede Mac OS to switches on the discrete graphic card.

Someone knows a way to set an arbitrary frequency on the discrete card? Or a configuration panel or similar?

Thanks