i had the same problem with my 2x Gigabyte 6950OC,one of them goes 85C and fans keep on 60%... i speaked with gigabyte support why is that card soo hot and asked them for normal working temperatures and maximum allowed which will not blow my card , they didnt actually answared me as i wanted but they say that it's normal, actually they said that this cards goes to100C on stress tests ,
to me after 85c is not going well

i currently manually set fans to 100% and hotter card keep around 72C if in my room temp is 30C card goes max 82 mostly keep around 78C

regards