Sorry, 2k is a typo. I want to ask about the difference between 2880x1080 and 4k resolution (as I'm using a 2880x1080 display and I know the crispness is indeed a lot better than 1920x1200). I thought a 2880x1080 is already very good and further increase in resolution would be barely noticeable.
2880×1080 is a super widescreen ratio (8:3, or call it 16:6 or 24:9 if you prefer); I don’t know how you intend to compare it to a regular widescreen ratio (16:9) which is only two thirds of the width for a given height.
It also depends on the screen size. Such super-widescreenness is probably only found in fairly large monitors, and at that size I’d say that doubling the resolution (5760×2160) will have a massive effect on perceived text quality. At that size, and depending on how far away from the screen you use it, you could possibly even double it again and still tell and appreciate the difference.
