It could also be that you a) do not have enough energy getting to your computer (ie.. not enough voltage)
b) You got some big dust clog in the fan causing it to overheat..
or c) it could be a driver related problem..
In any case I would suggest to get it changed since it is under the 1 year warrenty (if not oem)
or if it is the dust go use a vaccum to suck out and dust clogs
Hope this helps