I'm skeptical of add-on programs that purport to automatically regulate fan speed. By what mode of magic do these programs accomplish the improbable? Do they lower or raise the voltage, which in the later case would burn out the fan motor.
The fan itself has to have a built-in logic circuit that senses the temperature and adjusts it according to your specifications.
One solution is to buy an interposing cable with a rheostat that has to be adjusted manually or at least contains a sensor that that can regulate the fan speed. In other words, this is a hardware, not a software, issue that requires manual intervention somewhere along the line.
People who claim that Speedfan or similar programs actually work aren't taking into account all the variables that affect temperature. Also, bear in mind that buying a more powerful replacement fan will not appreciably affect your electric bill. Well-designed fans aren't noisy.