Resolution issue iMac 21.5” late 2013


macrumors newbie
Original poster
Dec 18, 2018
Hi guys, never done this sort of thing before but I have an issue.

I own a late 2013 21.5” iMac and recently purchased a monitor to edit my photos (I’m a photographer). The monitor I purchased was a 32” HP Pavilion. When I connected my iMac to the monitor I was only getting 1080p resolution instead of the maximum for the monitor which is 2560x1440.

After looking into it a bit I realised it was due to my iMac. I tried the monitor with my more up to date 2017 MacBook Pro and it worked a treat.

However, I’m losing significant RAM by using my MacBook which is effecting my editing.

My question is, would I be able to upgrade the graphics card in my 2013 iMac and would this mean I’d be able to maximise the resolution with the monitor? How much would this roughly cost or is it worth upgrading my main iMac altogether?



macrumors 68020
Jun 13, 2015
Video Support and Camera
  • FaceTime HD camera
  • Simultaneously supports full native resolution on the built-in display and up to a 30-inch display (2560 by 1600 pixels) on an external display
  • Support for extended desktop and video mirroring modes
  • Support for Target Display Mode via the Thunderbolt port using a Thunderbolt to Thunderbolt cable (sold separately)

Perhaps the cable/adaptor doesn't support 1440p.

It might be a good idea to mention the exact model of the monitor and connection type.


macrumors regular
Feb 16, 2009
I also have a late 2013 iMac and last week connected a 27” monitor with 2560x1440

At first the iMac output 1080 to the monitor but then I went into the display preferences and set the resolution to “best for this display” and it switched to full res

I think it was down to the fact that the iMac has to “increase” the resolution whereas the 2017 MBP is already outputting a greater or similar resolution to its own screen