When idling from the cleanly installed Ubuntu 12.04, the results are now in-line with the Ubuntu 11.04 power levels. The Ubuntu 12.04 power consumption with Intel Sandy Bridge hardware is in much better shape for the Precise Pangolin largely because the RC6 power-savings support is implemented. RC6 was problematic at first, but now it is sane to have enabled by default, which can lower the power consumption while boosting the OpenGL performance in certain conditions.
OpenArena is one of the games where the performance goes up in Ubuntu 12.04 for Intel Sandy Bridge "Gen6" graphics due to having RC6 plus the various Intel DRM and Mesa 8.0 DRI driver improvements made over the past six months and covered in numerous articles.
While the OpenGL frame-rate is up sharply, the RC6 power-savings does cause actually greater power consumption when the game is running. Ubuntu 11.04 OpenArena results are not available since with the Natty Narwhal the Sandy Bridge support was too shoddy. For those that don't remember the initial problems, here's OpenArena when installing Ubuntu 11.04 on the Sandy Bridge notebook.