1440p vs 2k vs 4k?

I've only seen 4k once in person, it was stunning. On a big 80 inch TV. Now I had gamed at 1080p and moved to 1440p, and I noticed the difference big time! I couldn't go back... Korean 1440 monitors are as cheap as good 1080 monitors.
 


Link?

Also, is 1440p 2K?
 
2k or 1440p would be fine for 760 sli. 4k might be quite an overspending. But if you don't mind on spending that much then 4k will look great, you will have to tweak down few settings from ultra to high, yes.
I would have gone for 3k. And for 4k if I had like 770 sli or something more powerfull gpu config like that.
 
OK 1440p is over 2k it's called 2.5k, 1920x1080 is 2k and "p" stands for progressive scan. it depend if you want a big monitor i would go with 2.5k that is 27" than 27" 2k monitor. but 4k it is not needed unless you want 29"+ monitor. you will need extreme rig to play games on ultra on 4k i got 55fps on bf4 with one titan z card worth $3k. if i was you just get a 24" monitor 2k monitor 60hz.
 


This is NUTS. The difference between 1080 and 1440 is massive and I would never go back. There are very close to double the pixels in 1440 compared to 1080. It dwarfs 1080 and make you feel restricted and confined when working with only 1080 vertical pixels, even for menial tasks like web browsing.