I have I think a somewhat unusual setup. I have 2 Dell Latitude E7470 Laptops connected to E-Port Plus docking stations which purport to support DP++ according to the manual, they also have DVI connectors. I have two HP 27q monitors which have DP, HDMI and DVI inputs. My 'home' E7470 is connected via DisplayPort cables to the two HP 27q monitors, and I get QHD resolution fine. The 'work' E7470 I've been having trouble getting QHD. I had DVI cables connected, and all I get is 1920x1200. I found out these were single link cables, so I ordered dual link DVI cables. Those didn't work. I see the light change on the monitor as though it is getting a signal, but the screen is black. I also tried DP to HDMI cables, same result. Does the 27q support QHD on the HDMI and/or DVI inputs? Right now I'm skeptical. I have ordered a VisionTek Active DP to DVI adapter to see if that will work. I've seen that perhaps the voltage output by DisplayPort is 3.3v, and DVI is 5v, which may be causing the black screen.