Well, you are kind of asking for opinions here. You cant put a number on what your eyes perceive because people perceive things in different ways. Theres guys here who have compared far more stuff then me.
well you can put a number on the density of the 'experienced' screens , it is the DPi/PPI, this alone defines the 'clarity'
My opinion then if its any use: I didnt use DSR very much when I had a 1920 x1200 24 inch monitor, the reason being on my GTX 780 at the time it didnt perform as well and it really didnt look that much better to me at all.
I wasnt blown away when I went to a 25 inch 2560x1440, but it's definitlely an improvement in action games. Bearing in mind that I didnt want to go to a 27 inch 1440 because I played with them and didnt feel that the image quality was much better then 24 inch 1080p, when you were comparing decent screens. 27inch 1080 to 27 1440 is going to be much more noticeable.
Having used a 1440 monitor when you go back 1080p does look worse then it used to. Whether its worth it is subjective, the best thing to do is see a friends 1440 monitor or go to a shop where you can demo it. Worst case scenario you can order one and send it back if youre not happy when comparing side by side and you can judge with your own eyes, because numbers really arent going to help.
Ok you have something to say, fine but please don't be surprised if i still ask some things later because i'm not sure then if you talk(ed) about DSRed 1080p or not when comparing with 1440p (and with different DPI).
Having used a 1440 monitor when you go back 1080p does look worse then it used to. Whether its worth it is subjective
Hence need for comparison
s see a friends 1440 monitor
Not any of my friends have that kind of screen, some still play on 1600x900 (gtx 760)
go to a shop where you can demo it
no real 'technical' PC shop around (hence no 1440p or 4k stuff)
Worst case scenario you can order one and send it back if youre not happy when comparing side by side and you can judge with your own eyes, because numbers really arent going to help.
Worst case scenario indeed, but i DO think numbers are going to help as i could compare the DPI+DSR values with some devices i already own (ie 440 dpi S4, current 91 ppi 1080p 24" screen, old crappy 13" netbook with low res,,,....etc)