yeah the coolbits haq...
in this folder (HKEY_LOCAL_MACHINE\\SOFTWARE\\NVIDIA Corporation\\Global\\NvTweak) create a new value called coolbits and set its dword value to 3. (I'm sure if you google coolbits you can find a program that will do it for you
then to navigate to the new interface
rightclick the desktop>
go to properties>click the settings tab>click advanced, then go to the tab called fx 5200 and go to temperature settings.
I am assuming you're kinda new at this, so try not to overclock the card until you understand how to a little better
by reading through this forum for countless hours lol.
and no putting a temp sensor on the heat sink will not give you an accurate temp. of your gpu