@Lion BItcoin Shop:

Getting to 71 W is not impossible but achievable by Trixx and WattTool- that's what I used - just adjust the GPU voltage slider while watching GPU-Z  GPU Load, Memory controller load and GPU Power Draw. If PC froze on you, or memory controller load just droppeed ,  you hit the limit, so tweak accordingly
In fact you can go under 70W if you underclock more, but I set my target to 28 Mh/s with reasonable power draw.

Last, remember evey card is different from the other, even they are same brand/model/lot, so some may require less/more voltage .