Yeah it could be the answer.

because when you look on my screen shot some answers befor, you can see my GPU-Z monitoring after 1h30 of Furemark and all the temperature are really LOW. If this component was used to be hot during operations, it may have beed monitored too.

I can try to put a thermal sensor on it to check if it's hot of not. I'll do this it's easy to access this side of the graphic card.