iGPU only MBP - can it drive 3 externals in clamshell mode?

Discussion in 'MacBook Pro' started by BicepsofPower, Aug 19, 2015.

  1. BicepsofPower macrumors newbie

    Aug 19, 2015
    I've been searching for an answer but can't seem to find it. This is for the 2015 MBP with Iris integrated GPU only. I know it can only drive 3 screens max, but if you're putting it in clamshell mode can you do 3 externals?

    Also, is anyone able to comment on iGPU only performance in driving 2 externals? I will never game or do photo/video editing (I have a desktop for that) so beyond regular usage I will only be using the GPU for driving externals. I will only be using 1080P monitors for the MBP.
  2. porkrind, Aug 20, 2015
    Last edited by a moderator: Aug 21, 2015

    porkrind macrumors regular


    Jun 30, 2015
    Well, given that they only have two video out ports...
  3. BicepsofPower thread starter macrumors newbie

    Aug 19, 2015
    Daisy chain? Splitter?
  4. Tankmaze macrumors 68000


    Mar 7, 2012
    Copy paste from everyman website :

    Apple reports that the "Early 2015" MacBook Pro models (MacBookPro12,1) as well as the "Mid-2015" MacBook Pro models with integrated graphics (MacBookPro11,4) support a simultaneous maximum resolution up to 3840x2160 on two external displays via Thunderbolt 2. Alternately, these models can support a single display up to 3840x2160 via Thunderbolt 2 and a single 1080p display at up to 60 Hz.

    In theory 2 display connect to thunderbolt port and 1 thru the hdmi should be possible, but I'm not sure about the heat generate from this.
  5. kevmodrome macrumors member

    Apr 8, 2015
    I'm using my rMBP 13" 2015 to run 2 4k monitors in clamshell mode. Works OK, UI is not smooth though. It should be able to run 3 1080p monitors with no problem since 2 4k monitors is the equivalent of 8 1080p monitors.
  6. BrettApple macrumors 65816


    Apr 3, 2010
    Heart of the midwest
    It comes down to an Apple/Intel support thing really. I've got a Late 2013 13" MBP and while I can physically plug in three monitors in clamshell mode, only two will work at a time. So, just two plus internal. I usually have one on HDMI and one on one of the Thunderbolt ports. Runs fine (2x 1080p + 2560x1600 internal).

    If you had to you can use one of those USB adapters but it won't get hardware acceleration and will be rather slow. But it would work for something like spreadsheets or a web page. Then you could have three external monitors.

    When I use clamshell mode and run two 1080p monitors it's pretty dang smooth. Smoother than the internal display running at 2560x1600 for sure. Mostly because it's running at non-retina resolution so there is no HiDPI or scaling going on. Your 2015 should be a bit faster than my 2013 model too.
  7. kevmodrome macrumors member

    Apr 8, 2015
    According to this guy 3-6 monitors is doable: http://mkn.us/blog/how-to-use-3-external-monitors-on-macbook-pro-2015/

    Edit: Nevermind, that seems to be for the 15".
  8. RoboWarriorSr macrumors 6502a

    Feb 23, 2013
    It should be able to run three 1080p displays, two on display port and one on HDMI theoretically. Whether or not performance is acceptable not too sure. I remember reading that two 1080p displays with laptop on run fine so a third should be okay especially when on clamshell.
  9. John6Plus macrumors 6502


    Sep 19, 2014
    Holland, MI
    I was just searching through the forums to see what I could find about multiple display performance and found this thread, though it's a little old.

    Anyway, I too have the 2015 13" rMBP and I just added a UHD monitor (4K? 3840 is NOT 4K!) in addition to a 1080p external I was already using. The UHD is on display port, the 1080p on HDMI. So I have three displays, for shorthand I'll use:

    Ret (Built in display, 2560x1600)
    UHD (Display port, 3840x2160)
    HD (HDMI, 1920x1080)

    Hey that's a lot of pixels.

    Here's what I've found as far as performance goes (everything I note is for desktop/2D use only, no gaming or such, just coding and remote desktop). I use a giant origami slide show across all the screens to monitor performance as well.

    Ret + HD: Perfect, no noticeable performance lag.
    Ret + UHD: Good, a slight hiccup slower than above, but not noticeable unless looking for it.
    Ret + HD + UHD: Eh, OK for most things, but noticeable and irritating lag more often than I'd like.
    HD + UHD (Clamshell): Good, but not perfect. On par with Ret + UHD, perhaps a little faster.

    What also is driven home by the above experiment is how gorgeous Apple displays are. I'd lick that screen. Hypothetically.
  10. John6Plus macrumors 6502


    Sep 19, 2014
    Holland, MI
    Added one more test: UHD Only. As probably expected it's perfect, no noticeable lag with any of my simple tests.

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