I recently got 3 QHD monitors (Lenovo L24p-10) with only 1x HDMI and 1x DP input ports.
My graphic card (Sapphire Radeon HD 7870 OC) has 1x HDMI, 1x DP, 1x DVI-D and 1x DVI-I output ports. Connected one monitor via HDMI and one via DP but as I tried to connect the last one via an DVI to HDMI passive adapter, problems begun as I am only able to get a maximum of 1920x1200@60Hz to this one while the other monitors work fine with 1440p.
As I understand passive adapters, the monitors requests HDMI signals, which is detected by the graphic card, giving out a HDMI signal via the DVI-D port requiring only the 19 pins of HDMI 1.4 (single-link in DVI cables) to get 2560×1600p@60Hz. The AMD Control Center (v18.2.1) also shows that two monitors are connected via HDMI and one via DP although it is the DVI-D port physically.
As other threads often suggest using the Custom Resolution Unit, I also tried that but CRU is already showing the correct detailed resolution of 2560x1440p@60Hz for every connected monitor. Also tried to activiate GPU scaling as this seems being a problem in v17 of the AMD drivers, ignoring the EDID information but this doens't help either.
Any ideas of how to achieve 1440p on all of the three monitors?
Thanks for every suggestions in advance!