13" 2015 vs 2016 - iGPU difference with ext monitor

Discussion in 'MacBook Pro' started by touchbearr, Jan 21, 2017.

  1. touchbearr macrumors newbie

    Dec 15, 2016
    Can anyone tell me the real world difference between the 13" 2015 and 2016 models (both nTB and TB) while driving higher resolution external monitors? What monitor are you using and is it smooth/lag free?
  2. RichardC300 macrumors 65816


    Sep 27, 2012
    Chapel Hill, NC
    Acer R221Q runs smooth with my 13" nTB MBP. Also tried briefly with an LG 5K monitor. Also smooth.
  3. pshifrin macrumors 6502


    Mar 14, 2010
    My personal experience:

    2015 13 inch to Dell 4K p2415q via 60hz display port: barely acceptable
    2016 13 inch to Dell 4K p2415q via 60hz display port: Great!
    2016 13 inch to LG 5k via included cable: Less than barely acceptable
  4. Aomin3 macrumors member


    May 30, 2016
    Are you referring to the 2016 13" with or without touchbar? Hm I'm surprised about the 2015 13" , isn't it supposed to handle a 4K display smoothly?
  5. brosenz macrumors regular


    Apr 26, 2011
    On the third case did you plug the 5K T3 cable on the left or right side? It should be left only, those are true T3 ports. Right ones are kind of a degraded ports
  6. keviig macrumors 6502

    Jun 7, 2012
    Dont expect any iGPU to run a 5K (15 million pixels) smoothly. It will run at 60hz, but animations and scrolling won't be smooth. Even the Radeon Pro 450 has some stutters here and there at that resolution.
  7. pshifrin macrumors 6502


    Mar 14, 2010
    Of course, on the left.
    --- Post Merged, Jan 22, 2017 ---
    13 TB 3.3/16/512
  8. mcomp112 macrumors regular

    Jan 1, 2017
    I returned a 2016 13 inch touch bar (2.9/16/512) because it stuttered during heavy workloads when connected to a 4K monitor (27ud88). My new 2016 15 inch (2.7/455/512) runs very smoothly though.

    Never used a 2015 13 inch.
  9. Christopher Kim macrumors newbie

    Nov 18, 2016
    I have the 13" tbMBP and run externally into an LG 27" UD68 4K monitor via DP (USB-C to DP cable) at 2560x1440 @ 60hz and it's very smooth. I've run it at true 4K resolution briefly and it seemed smooth, though didn't test extensively (watched a 4K video on Youtube).

    I have a question in terms of how Macs run retina mode. If for example you got the 27" LG 5K monitor and ran it in retina mode (ie. "looks like" 2560x1440), is that the same "burden" to the computer's gpu / processing power as if it were powering a native 1440p monitor? Or does it require more power (because it's not just doing a simple 4:1 conversion, but is doing some kind of additional smoothing)? And if it requires more power, is it the same or less power than if it were pushing a true 5K resolution? Anyone know?
  10. keviig macrumors 6502

    Jun 7, 2012
    Do you mean you run it at 2560x1440 retina resolution or just plain 2560x1440?

    As far as I understand it, with retina resolutions you render double the resolution. So for 2560x1440 retina on a 4k display you actually render 5120x2880. While at "true" 4k resolution you render 3840x2160. If you were to set it to 1920x1080 you'd still render 3840x2160.
  11. Christopher Kim macrumors newbie

    Nov 18, 2016
    Yes, I meant run it at 2560x1440 retina (so in macOS display settings, you would set your 5K monitor to scale to "looks like 2560x1440"). So you're saying it would in fact render 5120x2880, even though text size will look like it would if it were 2560x1440 native. So I'd infer then that it would basically use the same amount of GPU / processing power as it would if you were just running 5120x2880 native (ie. "looks like 5120 x 2880").

    That's helpful to know, that it doesn't matter if you run the 27" LG 5K Ultrafine at native resolution (would be crazy anyways), or 2560x1440 retina, both will use the same amount of processing power.

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