I might try this aswell. My junction temps are +30c higher too, albeit I'm running the card at 2100mhz with 1190mv and 50% power. It's getting darn close to 110c when I was looping 3d markPulled the Cooler off again, the top of the die had a very thin layer (Almost none) in the middle with a thicker layer around the edge, i don't think the cold plate on the cooler is completely flat.
Reapplied, spread it out... put the cooler back on, Edge Temps are still around ~70c with the junction Temps back down to ~95c, so from a 45c Delta back to a 25c Delta.
Lets see how long it lasts.