Comment 5 for bug 52852

When I "saved" (submitted) the above message, one of the core frequencies shot momentarily up to 100%, only to quickly settle down to 54% again in a number of steps. So, I don't think that the problem is CPU frequency related...

One difference that I notice is that without input activity the screen switches to half-bright very quickly, and then dims completely with the computer going to sleep not much later.
In Ubuntu this does not happen (the screen will switch to screensaver, which is not the same), and will not automatically go to sleep. BTW, the sleep function works OK on closing the lid, requiring password to get going on wakeup.

Could it be powersupply related then?