Allright, but doesn't there is a kind of relation between those two?
Not really, the heat sink on the VRM on these boards is pointlessly small. I think that airflow over the back of the card is much more important than worrying about the GPU temp.
When I ran mine, I had little heat sinks stuck to the metal plate on the back, and a fast 120mm fan blowing down the back of the two cards. Brought the VRM temps down significantly.