I use to run SLI and have since swapped to one card. Life is so much easier with one card, setting up Linux, running other programs, game optimization.
So, I finally got my 1080 ti and it plays games on my 3440x1440 at 70 to 100 fps. Witcher 3 drops to around 70ish in the city, 90's in the wild. Mass Effect Andromeda is capped at 100 but the janky game play is another thing.
Things will be better soon when my water block and tubing get here so I can OC it effectively.