In this brief, a practical power optimization method that calculates the optimal power supply and body bias voltages, for a given target operational frequency and a temperature, is proposed and evaluated. The proposed optimization method is based upon a simple power model in which several coefficients for leakage power, switching power, temperature, and operational frequency are obtained from accurate real chip measurements. The calculated optimal-voltage settings by the proposed model can achieve minimum accuracies of 93.8%, 91.6%, and 79.5% for room-temperature, 50 degrees C, and 65 degrees C, respectively. Since the proposed methodology is based on well-known power formulas, it can be applied to the latest FD-SOI technologies.