I hope Ubuntu folks will come with the fix soon.
Ubuntu 9.04 overheats my notebook
For last few days I observed my notebook (Sony vaio FZ140E) was heating up too much. Also battery could last for only 15 mins to half hour max. I thought it's EOL(End Of Life) phase of my laptop. But then, for some reason, when I booted it in Vista, the problem was not there. A little googling suggested that there is some bug in the ubuntu that is causing this issue. I am not at all aware with all the cpu cycle/frequency related terminologies quoted, but it has got something to do with percentage of processor usage. A lot of people seem to have same complaint. So the culprit is not my notebook :)