I am using Retina Display Menu (RDM) to give me a higher resolution for my MBP, and the sweet spot that I have found is 1920x1080.
However I get 2 different display options for this resolution depending on the monitor I am connected to - Acer V243HQ (regular) resolution - Samsung U28E590D 28-Inch
However with the Samsung I get the attached where the resolution has a lighting bolt which actually shows the text well rendered
My question is why does this happen only with specific monitors, and how can I get this even without having to plug my external monitor
UPDATE 1: Could it be that the Samsung has 4K support? could it be related to that?