2way SLI works out of the box for all 1070 and up cards (not 1060 last I checked), but 3/4 way SLI is not officially supported
Never for the 1060 since the ports are removed. Unless they go AMD route and put the data through the PCIE Bus. But that isn't going to happen anytime soon I have a feeling, not with the HB Bridges Nvidia hyped.