My buddy just bought a 100hz, curved IPS panel (TN panels will not get hit as hard as an IPS will, and wont stutter as much, but wont look as good either), 21:9 monitor like you are talking about.
He has an 8700k, 32gb memory, and a 1080 ti. No oc.
He gets good frames in the latest titles we play, but gets some dips in some setions (just like a 2080 will do).
But, a 2080 is supposed to be a bit better at larger resolutions than the 1080 ti is, so I would say go for it, I think the 2080 will be fine.
If you dont want dips, go sli or 2080 TI.
I have a 9700k, 32gb memory, and HAD only 1 2080, at 2560x1440 @ 144hz IPS. The single 2080 didnt really work well (for ME, but I am very finicky with dips and stutter, it makes me nauseous). A 2nd 2080 later, and it is perfect for my (real 2k) system. I dont get dips anymore, and I can also upscale to true 4k (then downscales to my 2k) without a hitch, except in Shadow of the Tomb Raider and Vermintide 2, some pre-cfg'ed scenes flicker a tiny bit). But, I could easily do 21:9 with or w/o the upscaling with sli. Heck, I could even do 4k @ 60hz with 2 2080's.
:)
post edited by Dave3d - 2019/01/12 23:49:59