Dual 4k @ 60hz - is it possible on a rMBP?

Discussion in 'MacBook Pro' started by givemepixels, Apr 16, 2015.

  1. givemepixels macrumors newbie

    Apr 16, 2015
    I've scoured the internet for hours, and can't find an answer to this question:
    Is it possible to run two 4k monitors at 60hz on a Macbook Pro?

    The only candidates appear to be the new 2015 13" rMBP with Iris 6100, or the 2014 15" rMBP with Iris Pro and the 750M graphics card. I've been given my choice of laptop for work, so I just want the one that will do this best. Obviously, this would be using the Thunderbolt ports, I'm aware this isn't possible with TB + HDMI.

    I've tested the 2015 13" and have confirmed it can drive a 4k monitor at 60hz, and a 2560 x 1600 monitor at 60hz at the same time. I've also heard that the Iris Pro can drive a 4k monitor at 60hz on its own, so theoretically that plus the 750M should work, right?

    I went to the Apple store and asked today, and got no answer. I'm amazed at Apple's lack of clarity in their specs on this matter.

    Anyone? I don't care if this will make graphics "choppy", I'm a software engineer so all I need is as much screen real estate as possible, I have no interest in smooth UI animations.

    I will most likely be using two Samsung U28D590D monitors in SST, since I already own one.
  2. Samuelsan2001 macrumors 604

    Oct 24, 2013
    A couple of things

    Yes you can run two 4K.

    The 750M variant only uses the dGPU for external screens (the iGPU is not connected to any of the ports)

    If you aren't worried about chopiness etc why worry about 60hz.... You can just use HDMI and 30hz for one it'll make no difference for text and code..

    Yes they are the only 2 current portable macs that can do this...

    Unless you need portability consider a 5K imac with your current screen as the second screen. More powerful and basically a free screen.
  3. givemepixels thread starter macrumors newbie

    Apr 16, 2015
    I've tried 30hz, but I hate the choppiness of mousing/scrolling. What I meant was I don't care if the window resize animations or mission control animations aren't 100% smooth, but I do need 60hz to prevent the mouse cursor slideshow.

    I just came across this thread, and it sounds like the 750M will disable the second Thunderbolt port completely once you plug in a 4k@60hz monitor:

    Since the office already has some 2015 13" Iris 6100s hanging around, I'll just buy the second monitor and test on one of those. If it works, I'll go with the 13". If not, I'll get the 15" for the extra horsepower.

    Of course, the new 15" rMBP is going to be able to do this just fine and come out a month after I get this laptop... all part of the yearly Apple upgrade squeeze I guess :rolleyes:
  4. JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
  5. givemepixels thread starter macrumors newbie

    Apr 16, 2015
    Awesome! I really appreciate your help! Just in time too :)

    The Apple store employee told me to please post on their forums if this was possible, it seems like something people are just now experimenting with.
  6. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle

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