I believe:
1) DP, or
2) Dual-link DVI
I suggest DP.
Other:
I suggest forcing on the "HALF Adaptive VSYNC" features for some games when you don't want screen tear. That will synch to 72FPS on the GPU side (but disable VSYNC if you can't output that much).
To do that:
a) NVidia Control Panel-> Manage 3D Settings-> "ADD" game
b) enable feature then save
c) run game and confirm it will cap at 72FPS