GC is a Saphire Radeon HD6800 @900Mhz with Catalyst 12.10
Isn't there a hidden key combo to display internal Frame-Counter (that would be very useful) ?

I'll try to log the Sensor to see the heating.

vSync is enabled; I don't know how to display the frame rate yet in arma3 but it shouldn't heat my GC on a static screen isn't it ? If someone can tell me how to display the framecounter I'll be glad to hear it.

To Paronity: it is the game problem because this is the game that drain power from my GC this is not my GC that decide to over-heat all alone. Beside this problem doesn't occur with other games and it can endanger the GC.