http://www.wsgf.org/mgl/uws
Also, there's no real reason to go 4k for gaming at its current state:
* A Nvidia Titan X or 1080 Ti won't be able to run current state of the art games maxed and at 120+ fps; with some of them can even struggle to reach 100 fps in 1440p. 4K is entirely outside of their reach (except if you want to run games with so-so graphics, which isn't bad, but why 4K then?).
* HDR support in PC gaming is weak and the results are poor. You can get better visual quality in consoles, but the best looking games in those are meant to run at 1080p x 60 fps, so again 4k has no sense.
UW is viable with current hardware and top notch games; provides more inmersion and a different gameplay experience and is wildy popular between new games released.