With your latest response, you indicate that this is the GPU (graphics card chip) and not the CPU (computer chip). Not that pretty much negates most of what has been said (certainly in my last post).

GPUs also tend to have a higher thermal range, so 80c might not be so critical. But it is certainly worth getting some compressed air and give the GPU Fan area a good blast (whilst the system is disconnected).

You might want to do a search (as I did to check out your CPU) for your graphics card as that could give you some useful information on its thermal ranges.