asus m5a78l-m-lx3

Heyho, I recently changed my motherboard to an Asus m5a78l-m-lx3. It has an 4 PIN CPU cooler socket, however - my cpu cooler only has 3 pins. I read about regulating it via voltage - but I'm not able to find anything except VCORE Voltage which does not seem to change anything if I lower it. I...