Late 2013 iMac 27' with 4k monitor - possible?

Discussion in 'Mac Accessories' started by jharvey71884, Nov 25, 2016.

  1. jharvey71884 macrumors 6502

    May 3, 2011
    So I'm looking to add a 4k display to my 27 inch Late 2013. If it's possible. I also am wanting to make sure it's 60GHz.

    On Apple's website, this is what it says. What the heck is a SST? Been searching on the internet and must be dumb, because I'm not following.

    Single-Stream (SST) displays
    Most single-stream 4K displays are supported at 30Hz operation.

    With OS X Yosemite v10.10.3 and later, most single-stream 4K (3840x2160) displays are supported at 60Hz operation on the following Mac computers:

    • MacBook Pro (Retina, 13-inch, Early 2015) and later
    • MacBook Pro (Retina, 15-inch, Mid 2014) and later
    • Mac Pro (Late 2013)
    • iMac (27-inch, Late 2013) and later
    • MacBook Air (Early 2015)

    Any help would be appreciated, especially if you have this setup?
  2. iMav macrumors 6502


    Jun 20, 2008
    Columbus, WI
    I just recently picked up a late 2013 iMac to, hopefully, drive a 4K display. We'll see once the monitor arrives.
  3. slammer0 macrumors newbie

    Nov 6, 2012
    Unfortunately it seems like the Apple webpage is wrong. It doesn't work for me. The display is LG 27UD68 and it works perfectly with 2015 MacBook Pro 15. Can we contact Apple somehow to ask how to achieve the 4K/60hz on this computer?
  4. iMav macrumors 6502


    Jun 20, 2008
    Columbus, WI
    I ended up just running the 4k display at 2560x1440 (which is the same resolution as the iMac display). I also have a third monitor that I am running at 2048x1152. (so I have plenty of screen real estate).

    As I am pushing 50, my eyes aren't that great I probably would have a hard time with full 4k anyways. :)
  5. andy9l, Jan 6, 2017
    Last edited: Jan 6, 2017

    andy9l macrumors 68000

    Aug 31, 2009
    England, UK
    You're more likely scaling it to 2560x1440, not actually sending a 2560x1440 signal to it. The difference being:

    With the former your iMac is still pushing all 4K pixels, it's just doing some on-the-fly calculations to map most UI elements to 1.5x their normal size (2560x1.5 = 3840).

    With the latter your iMac is sending a low resolution 2560x1440 signal to the monitor and it'll either be horribly blurry or have huge black borders, depending on how the monitor decides to handle that signal.

    In other words you're probably still running 4K, but scaling up the UI so it has the same physical size as a 2560x1440 monitor. The quality should still be significantly better on the 4K screen, but there will be some blurriness due to 1.5 scaling (no such thing as half a pixel!) as opposed to a perfect 2.0 scaling that you get with retina displays from Apple. For a 4K screen, perfect 2.0 scaling would be 1080p (1920x1080).
  6. ebeck macrumors newbie

    Jan 15, 2018
    Hey slammer, I have a late 2013 27" imac and just got the same LG monitor and can't even get it to go above 1920x1080, 30Hz. Are you able to run it at 2560x1440?

    I'm using this displayport mini to display port cable

    The only options I am seeing as resolutions are: 1920x1080, 1600 x 900, 1280x720 and "1080p" which makes the image shrunk down in the center of the LG monitor.

    Any tips would be helpful.
  7. slammer0 macrumors newbie

    Nov 6, 2012
    @ebeck My cable looks the same, it supports higher DP version than the iMac. Have you tried holding option while clicking on the "scaled" radio button? It should give you more options. I don't recommend displaying 2560x1440 at this display as it is very blurry. 1080p 60Hz or 4k 30hz are the best options depending if you prefer sharpness or smoothness. I personally use currently some cheap mini DP->HDMI cable for the iMac and I'm able to set 5k resolution scaled to 4k (in 30Hz) and the DP port on the display is used by MBP that supports 4k in 60hz.

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