How to reach full resolution potential with MacBook Pro 2012? 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
HDMI is limited to 1920x1080. You will need to connect the monitor with a mini DP to DP cable.