I've been running GTX 980Ti SLI for a couple of years now. I think. Decided it was time for an upgrade.
I must say, I really wanted the RTX 2080Ti, but nVidia priced that one out of my range. Honestly the price is ridiculous. Seems like what used to be Titan, is now just their top tier. Both in performance and price point.
Anyway the RTX 2080 equals 1080Ti I think, which again matched 980Ti SLI I believe. More or less. For me it means I get quite a lot more performance in most games, except those that had nearly perfect scaling with SLI. At less than half the previous power consumption, equaling much less heat to get rid off. :D