The present disclosure relates to a predicative power management system configured to adjust computer CPU clock rate by a computer user to conserve energy based on user category. In certain embodiments, the predicative power management system includes (a) a computer user profile creator module, and (b) a power management module. The computer user profile creator module is used to create computer usage profiles and each of the computer usage profiles has a profileID for a computer user with a computer userID. The power management module is used to set and adjust computer CPU clock rate, CPU voltage and device states based on computer users' category and the computer user's computer usage profile.