4K (3840 by 2160) with the new rMB

Discussion in 'MacBook' started by iRun26.2, Mar 21, 2015.

  1. iRun26.2 macrumors 68000

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    Aug 15, 2010
    #1
    Supposedly the new rMB can connect to an external 4K monitor. Does anyone (besides me) think they might put this feature to use?

    (I'm going to see if my boss will pay for one at work)
     
  2. Mcdevidr macrumors 6502a

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    #2
    Are there any laptops using the core M with DisplayPort outputs? I can't find any to even see if 4k is supported at a decent refresh rate.
     
  3. tx26257 macrumors member

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    Mar 13, 2010
    #3
    There was a big debate over this and the ability to do it. Some people where concerned about usb-c and other would heating be a problem.

    I think it will be the refresh rate that is the problem
     
  4. anthonymoody macrumors 68020

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    #4
    Thinking about an rMB + 4K monitor for a birthday present for the Mrs. but not until/unless I get trusted 3rd party verification that it works well.
     
  5. maflynn Moderator

    maflynn

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    #5
    Correct me if I'm wrong but the current 13" rMBP cannot drive a 4k monitor, so if that's the case, then I'd say the 12" is unable to as well.
     
  6. Ulenspiegel macrumors 68020

    Ulenspiegel

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    #6
    Mike, according to one of the Members it can: http://forums.macrumors.com/showthread.php?t=1856116.
    Nevertheless, the question still remains in case of 12" rMB.
    Personally, I don't think it will be capable, but we will see.
     
  7. MyopicPaideia macrumors 68000

    MyopicPaideia

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    #7
    It can. Apple's product page tech specs list that resolution as its max "up to" for an external monitor. USB 3.1 does native mDP 1.2, so it is obviously technically possible. However, Apple curiously isn't providing a USB-C to mDP port option in their multi adapter offerings, just HDMI or VGA, neither of which are capable of the high resolution, so you're getting a max 1080p there.

    Interesting to see if a USB-C monitor or two will come out, and failing that, a USB-C to mDP adapter. Shouldn't really be a technical reason why Apple didn't provide one to begin with...especially if they are going to list that spec on the product page.
     

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  8. MyopicPaideia macrumors 68000

    MyopicPaideia

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    #8
    Yup, it can, two external monitors simultaneously at up to 3840x2160 resolution while running its own at native retina resolution. Not "true" 4k, but close enough.
     
  9. maflynn Moderator

    maflynn

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    #9
    Thanks for the clarification/correction guys. I was wrong, but I wasn't totally sure.
     
  10. iRun26.2 thread starter macrumors 68000

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    #10
    How in the world could a 5W part be able to drive that many pixels? It seems like it wouldn't have any power left to do anything else.

    It would be quite a sight, though: One of the smallest of computers driving one of the biggest monitors.
     
  11. ctyrider, Mar 21, 2015
    Last edited: Mar 22, 2015

    ctyrider macrumors 6502a

    ctyrider

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    #11
    Why? I have my tiny 11" MBA driving dual 27" Thunderbolt displays without breaking a sweat.

    Apple wouldn't be listing 4K as supported external resolution in rMB specs, if it wasn't capable of it. Modern GPUs are surprisingly good even in ultra-portables.
     
  12. Soordhin macrumors member

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    Berlin, Germany
    #12
    HDMI from standard 1.4 (partly) and 2.0 (fully) supports 4k. However the apple adapter so far only lists up to 1080p as supported resolution. But i'm sure the third party market is already gearing up to provide the full mDP support that apple currently does not provide with its adapters.
     
  13. chleuasme macrumors 6502

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    #13
    There is this: http://www.intel.com/content/dam/ww...s/core-m-processor-family-datasheet-vol-1.pdf (p.26)

    To support maximum display resolution of 3840 x 2160 @ 60 Hz on DP or eDP, extra cooling is required and only two displays can be supported as shown in the table.

    So don't expect to drive two 4K external displays, and only one already seems unsupported with a fanless design.
    Maybe the rMB can only support one 4K@30Hz?
     
  14. Miltz macrumors 6502

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    New York
    #14
    Based on everything I've read on the Intel 5300 it should support ATLEAST one 4K display. Which I think is enough. Who's going to buy a Macbook to drive two 4K displays anyway? My 2013 Macbook air ran my 2560x1400 display with ZERO problems, yet forums were filled with people saying it didn't support it.
     
  15. iRun26.2 thread starter macrumors 68000

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    #15
    That's good to know. I think it could make the new rMB more valuable for me for some of the CAD tools I use (schematic capture and PCB layout design) if I could connect it to a 4K monitor.
     
  16. chleuasme macrumors 6502

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    #16
    rMB users will be able to use a 4K (3840x2160) secondary display, Apple is giving clear info on that. No debate.
    But given the Intel specs, it likely won't be supported at 60Hz.
     
  17. iRun26.2 thread starter macrumors 68000

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    #17
    Under what circumstances would 30Hz be noticeably worse than 60Hz? How about CAD software (schematic capture and PCB layout), would 30Hz look acceptable?
     
  18. chabig macrumors 68040

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    #18
    That works? It's not supported, according to the specs. http://www.apple.com/macbook-air/specs.html I run a single TB display off mine. Running two would be fantastic!
     
  19. ByteTheBooty macrumors regular

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    Mar 8, 2015
    #19
    This may not completely apply to this thread, im planning on getting a 4k TV .... does apple TV allow you to mirror your mac in 4k resolution??
     
  20. ctyrider macrumors 6502a

    ctyrider

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    #20
    Yes, it's been supported for years.

    Of course not. Apple TV itself can only output up to 1080p resolution - that's what AirPlay mirroring is limited to.
     
  21. chleuasme macrumors 6502

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    #21
    Choppiness with the low framerate should be visible with any scroll in a page or in OS X visual transitions, adding in the second screen to drive and the large resolution.
    For a usage like displaying static images/pages aside the MB screen, it shouldn't be much frustrating, but you probably wouldn't want to use a 4K@30Hz display as your main computer screen to browse the web or scroll through PDFs and stuffs daily.
     
  22. Mcdevidr macrumors 6502a

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    #22
    I keep reading that 60z will need passive cooling. I hope that doesn't mean I won't be able to increase the screen real estate to 1650x1080 or higher.

    Maybe apple should have asked microsoft to borrow the fan from the surface pro 3 and done some apple magic to it, to make it smaller and thrown it in so we could have 4k at 60z.
     
  23. chleuasme macrumors 6502

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    #23
    Active cooling appears to be necessary only for driving a 3840x2160 screen at 60Hz.
    The maximum resolution supported by the new rMB wil be equivalent to 1440x900 (HiDPI 2x 2880x1800 resolution scaled down to the 2304x1440 grid of pixels of the screen). It will not need active cooling and supposedly Broadwell Core M should support it at 60Hz.
     
  24. asus macrumors newbie

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    Oct 17, 2014
    #24
    It can't, it's not possible.

    USB-C has max 10 Gbits/sec bandwidth.

    4k 60Hz 4:4:4 needs around 12 Gbits/sec

    bit_per_channel = 8
    – num_channels = 3 (RGB)
    – resolution = 3840 * 2160
    – 60Hz = 60 times per second
    – bandwidth = 3840 * 2160 * 8 * 3 * 60
    – bandwidth 4k@60Hz = 11.94 Gbits/sec

    Case closed
     
  25. rkuo macrumors 6502a

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    Sep 25, 2010
    #25
    Displayport alternate mode runs over the same physical wires but does not use USB-C natively (since display bit error rate is much more forgiving than real data). So yes it is possible.
     

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