http://gb.releases.ubuntu.com//precise/ Beginning with the Beta-1 kernel we have also enabled RC6 by default for Sandy Bridge systems. RC6 is a technology which allows the GPU to go into a very low power consumption state when the GPU is idle (down to 0W). It results in considerable power savings when this stage is activated. When comparing under idle loads with machine state where RC6 is disabled, improved power usage of around 40-60% has been witnessed. Up until recently, RC6 was disabled by default for Sandy Bridge systems due to reports of hangs and graphics corruption issues when RC6 was enabled. Intel has now asserted that RC6p (deep RC6) is responsible for the RC6 related issues on Sandy Bridge and corresponding patches have been submitted upstream. In an effort to provide more exposure and testing, the Ubuntu kernel team has applied these patches to the Beta-1 kernel and has additionally enabled plain RC6 by default on Sandy Bridge systems so that users can benefit from the improved power savings by default. We ask that anyone interested in testing and providing feedback to please refer to the PowerManagementRC6 wiki.