I would like to clarify some aspects of resolution requirements for you to understand better the situation.
Passive adapters will not go above 1920x1200p
Dual Link Active adapters will go above 1200p
Now, you have 3 ports, DP (2560x1440p max) , DVI-I (2560x1440p max) & HDMI (1920x1080p max). Which port do you want to use with a USB Graphics adapter?