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.