PoE on a 21:9 or 4K display - any experiences?

So yeah, I'm on the hunt for a new monitor, and I've seen these wide displays and have to admit I'm quite intrigued. I was looking at a 34" display (by Acer I believe) today and it looked stunning with that much screen estate.

How's PoE running on a wide display? I've searched around a bit and only found some noob players on Youtube showing it off (no offense). Would be nice to know how it runs when things get hectic in endgame, and what kind of hardware you're using to pull it off. What kind of FPS numbers are you seeing?

The resolution I'd run it at would be 3440x1440, and I have an i7-6700K and a 980Ti card. Currently I'm playing on a borrowed 27" 2560x1440 display (60Hz) and that runs well. But, I need to return it soon so it's time to buy myself a new one. I'm hoping the 980Ti will survive at least until the next generation arrives, maybe 1080Ti or something.

Second option would be a 4K display but those are even harder to run (FPS-wise I mean) and are only 60Hz for now. Not sure what I should try, could use some ideas.

The general idea is: I want G-SYNC and higher refresh rates, and as much screen estate as possible, and under no circumstances a TN display. I don't play shooters & action stuff, nearly only RPGs and MMOs with some strategy stuff mixed in so in theory I should be okay with 60Hz. I saw one of those 144Hz displays though and it's just so..smooth. I'd really like that in a larger screen. And G-SYNC is a requirement.

Reason asking here is of course due to PoE - it's my main game and I can't really find much info elsewhere. Any suggestions would be most welcome. :)

I bought an ultrawide and had fantastic experiences in several games, witcher 3, gta five, guildwars2 etc ... and I will not go back to the conventional 19:9, but know that not all games behave well (bathesda games for example), So in poe I'm having problems with dx11 high drop framerate and dx9 does not work 21: 9 for me, blackscreen, freezes, pc crash and other issues, oing through some problems, we have a very advanced view in relation to 19: 9 in exchange for possible technical problems.

ps:Sorry for bad English

Thanks Gabriel, yeah I'm particularly keen to experience things like Witcher 3 and WoW on 21:9, that seems like a dream. Sorry to hear you had some problems with PoE though. :/ What graphics card & CPU are you using?

I'd love to hear from someone who has experience with 4K in PoE.