Try going to the start menu and typing "scaling". You should get "make everything bigger". Go there and change it to 100%, any difference?
I have AMD cards, not nVidia, but AMD software allows independent display scaling of the monitors. You might check your nVidia software if it does the same, and what the settings are.
Both monitors are 27 inch, 2560x1440; shouldn't they be able to display the same contents on the screen?