Can 2015 15" rMBP w/ M370X run two 4k monitors at 60hz?

Discussion in 'MacBook Pro' started by Wade Vose, Jun 9, 2015.

  1. Wade Vose macrumors newbie

    Wade Vose

    Joined:
    Jun 9, 2015
    #1
    I have a new 2015 15" Retina Macbook Pro with the AMD Radeon R9 M370X graphics card. I also have a Monoprice 28 in UHD LED 4K 60Hz monitor with DisplayPort input, with a native resolution of 3840x2160/60 Hz. The rMBP drives this monitor wonderfully at 3840x2160/60 Hz with a DisplayPort 1.2 to mini-DisplayPort cable.

    My question is, can my rMBP drive a second identical monitor at the same resolution and frame rate? In other words, can it drive dual 3840x2160/60 Hz monitors, if each is connected to one of the two Thunderbolt ports?

    Apple's tech specs page for the 2015 15" rMBP is unclear on the matter. It says:

    Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors​

    But it doesn't say whether it can do them both at 60 hz.

    Has anyone tried this yet? I'd like to know before I order a second monitor!

    Thanks!
     
  2. Dark Void macrumors 68030

    Dark Void

    Joined:
    Jun 1, 2011
    Location:
    Cimmerian End
    #2
    I haven't the opportunity to try it, but I don't see why not.

    It's a mid-range GPU however, so it would help to clarify what exactly you mean. If you just mean simply plugging them in and having two functional displays both running at identical resolutions and refresh rates, then again, I don't see why not. I have searched related threads and I don't see any reason.

    In terms of GPU-intensive tasks though, that card may have trouble pushing two 4K displays simultaneously.

    Hope this helps.
     
  3. rdav macrumors 6502

    rdav

    Joined:
    Mar 16, 2007
    Location:
    So/California.
    #3
    Curious about this too. Assume that Apple support have left it vague for some reason. Perhaps the (2015)MBPr(11,5) can run 2x UHD(4k)@60Hz via TB2x2 - but only with undemanding applications, or in clam-shell mode.

    Some general notes here, but nothing definitive yet:
    http://www.everymac.com/systems/app...-to-manually-switch-graphics.html#extdisplays

    I think some punters on this forum were sucessfully running 2x Dell-P2715Q monitors on the (2014)MBPr(11,3) - but I don't know how hard they were pushing the performance.
     
  4. rdav macrumors 6502

    rdav

    Joined:
    Mar 16, 2007
    Location:
    So/California.
    #4
    Anyone else had a chance to test this yet?
    Inquiring minds need to know... (thx).
     
  5. jptaranto, Nov 15, 2015
    Last edited: Nov 16, 2015

    jptaranto macrumors newbie

    Joined:
    Nov 15, 2015
    #5
    The M370X can definitely run two displays at 3840x2160 at 60hz, however I've no idea at what performance hit.

    For example does the fan run constantly? how does the fan go with all three displays? can you watch video on one display and work on another without a performance hit/serious fan spin up? how smooth are animations like El Capitan's mission control? etc.
     

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