Have not had time to fully test however my card runs way better now the bios has been modded with v0.5 allowing me not to use more voltage.... maybe my card hates it!!!

I changed only fan speed to min 50 & power target to 160% left voltage @ 1150000 & the card runs fine on stock 1085 core. The fan speed min was 50% in windows however it did not rise as the card got hotter & the card sat at 1085 as it looks like the extra power target max was not applied.

I then used Afterburner to increase the target to 160% & the card boosted up to about 1160 ish using about 130 ~135 TDP @ 1.175v until it got upto 70oC + & began to throttle voltage down to 1.16 something & speed down a little maintaining 74oC. Voltage was measured just using GPU-Z/Kombustor

I also v quickly tested adding more core speed/boost up to 1250 & the card ran until it throttled & I also moded & flashed a bios with lower voltage 1.135 & it ran however I have not fully tested whether it boosts correctly etc. Interesting thing is the boost logic only looks to add about 2 voltage clicks i.e set 1.15 & it boosts 1.1675 then 1.175 according to software anyway.