It's better to set the speed to automatic and let the BIOS decide what the speed should be. If this does not seem to solve the heat issue, then look for the problem elsewhere. Thermal compound properly applied?
I did not really had a heat issue, more that the fan spinned a little too much. I have now tried to adjust it through BIOS and the RPM did go down from 2000 to about 900. The CPU core temperature went from 20 to 30C, but I guess that is still not much.