A microprocessor temperature control system including a microprocessor with on-chip fan control logic, a fan, and temperature sense logic. The fan control logic receives temperature information and provides a variable fan control signal to cool the microprocessor. The fan is externally mounted to the microprocessor and has a control input that receives the variable fan control signal. The temperature sense logic provides the temperature information associated with the microprocessor. The fan control logic may be configured to vary rotational speed of the fan and to adjust operation of the fan to achieve an optimum blend of reliability, power consumption, and speed. In addition or in the alternative, the temperature sense logic is external to the microprocessor for providing the temperature information via an external interface. The fan control signal may be a variable output in digital format.