I have a MacBook Pro (13-inch, Mid 2012) running OS X El Capitan version 10.11.4. I am attempting to use an external display with my Dell U2715Q (has 4k capabilities). I purchased an AmazonBasics miniDisplayPort to HDMI adapter and I am getting 1920x 1080 as my max resolution.
My question is: how can I obtain the full max resolution with my mac and monitor set up?
According to the official website I should be able to reach 2560 x 1600:
Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 2560 by 1600 pixels on an external display, both at millions of colors