Comment 153 for bug 22336

I think there is bug on handling thermal in Ubuntu. There are 2 approaches:

1.- slow down everything: this is what microsoft windows is doing, just install MobileMeter (http://www.geocities.co.jp/SiliconValley-Oakland/8259/), play your favorite windows cpu intensive game and see. If your system is getting hot, windows slow down to the minimum (800Mhz). I found out that all my games are played at the lowest speed because of temperature problems.
2.- Tell the user that reached a critical themperature and *SUSPEND* the machine. It may be RAM or disk.

In my case, the problem was the fan were really really dirty. I've cleaned and now everything is fine. Some pictures are here:
http://img187.imageshack.us/slideshow/player.php?id=img187/557/1178842006ygq.smil

HTH,