I can't believe this worked. Thanks a lot. I was scratching my head on how to force my thinkpad t430 to display full resolution on my ultrawide monitor. Adding a custom resolution like it's mentioned in the article worked for me. Only changed I made was instead of using 24 for frame rate, I used 50.
I added the custom res in custommode app on Samsung Ativ Book 8. But the option is still not coming up in intel settings or Windows display settings. I am trying this with BenQ PD2700Q via HDMI btw