P157sm 8970m Heatsink

So I purchased a Sager NP8255-S (Clevo P157SM) with an amd 8970m a couple months ago, and have just recently been playing some games on it (don't ask why, just been preoccupied with schoolwork). But I began to notice something, whenever I play a graphics intensive game like BF4 or ACIV, the GPU load will be at 100% and within 10 minutes the GPU will reach over 100C and begin to throttle itself. At first I thought it might have to do with that crappy OEM thermal paste on the GPU and CPU, so I replaced it with some Noctua NT-H1, put it all back together and... same story. It definitely isn't a room temperature or ventilation problem, as I have it on a desk in an air conditioned room, so this seems to single out the problem as being the heatsink itself. I remember seeing this in another thread about a guy who had a 780m reaching around 100C and throttling, then going out and buying a new heatsink for it and lowering the temps to the mid 80's. Would it be possible to get a new heatsink for the 8970m, and if so how? (Also, what do you guys think the problem is, because I might be wrong about the whole heatsink thing?)

 

New system? Let warranty fix this for you. Unless you want to learn/waste time doing it yourself.