Concerning Xorg, look through the log file /var/log/Xorg.0.log, e.g., the command $ grep -i dynamic should tell you if power saving ("Dynamic Clock Scaling") is enabled or not. Generally, the problem of energy consumption can be tackled with the program powertop best called as root. Maybe, it can tell you the culprit for the observed cpu usage. Regards, Jörg-Volker.