Lol, I though we were talking about CPU and GPU today in the game... my apologies.
Ergo,
I've had a case like yours in the past with an older Nvidia GPU. Don't waste much time nor resources with in case you've revised and cleaned its fan, any other dirty which could be lowering cooling, et cetera...
These GPUs degrade and several malfunction end up occurring. My older GPU was having the same issue: Abnormal Overheating before finally dying or went kaput.
There are many options which are relatively cheap within the, for example, Nvidia 700 series. I'd suggest you something like the Geforce gtx 750Ti 2GB or higher. These aren't so expensive right now.
Seems to be that It's time to upgrade there at your end. Hope this is of any help for you, mate. ;)