I don't believe the GF4 had such sensors unless they were installed by an OEM company. I know Gainward claims to have temperature sensors on my ti4400, but in order for that to work I need to use their drivers, which are somewhat older, and it's not that important to me anyway. Voltage, maybe there is some way, but unless the company that built your GF4 claims that there are temperature sensors on it, there aren't.