M17x r2 580m backplate idea

So I was doing some research on the 580m from the m18x and i realized that they have a fancy backplate that helps with cooling and I realized i didn't have this and by the looks of it, this is a needed item, the backplate has a kind of a heatsink to it for the backside memory and this i think will assist with keeping the card cooler and being able to stop it from shutting down cause as of late when I play far cry 3 this card i have seems to get up to 78C and it sits there but after about an hour it shuts down. I'm thinking I'm missing something and this could be the key to making so the laptop doesn't just power down. No other game does this to my laptop, so take a look at this and tell me if its a must since its a 580m. Alienware NVIDIA Video Card M18x R1 R2 Heat Sink Spreader 680M 580M Left Side | eBay

plus anyone know of the points on the card that i need to make sure have some sort of thermal contact, i went off what looked to be right from others but i just want to know the layout of the thermal pads on the 580m that are suppose to be there and if im missing some ill create some add on to get those parts cooled.