Alright thanks to both of you!
I've first disabled gpu 1 but it was laggy as hell ingame because of the intensity of the other two gpu's.. so I slowly put the intensity lower until I was satisfied with the ingame performance and ended up at intensity 12 (of formerly 19). Also I enabled gpu 1 again and felt no difference.
So I'm able to play TESO at ultra settings while still having 65% of my usual mining output