ok i reapplied the thermal past (had the corsair preapplied stuff on there and is fucking SUCKS, didnt even melt once, was still on layer on the waterblock!) temps are reduced now, but i cant apply a lot of pressure on my CPU, since my board just wont boot then (Asus Maximus Hero VII). Semms like a well known problem, the board cant handle a lot of pressure! So now my waterblock is just sitting very loosly on my CPU (i can move it arround without a lot of force)
ran 20min stress test and i never saw 90°c anymore, max was 85°C average on 70-75c