Rmbp connected to 4k monitor problem

Discussion in 'MacBook Pro' started by Roadking714, Jul 4, 2016.

  1. Roadking714 macrumors regular

    Joined:
    Mar 7, 2014
    #1
    Every now and then upon waking laptop it switches resolutions anybody know why? also speakers that are connected to headphone jack tend to be unconnected which I have to head back to system preferences and reconnect sound
     
  2. campyguy macrumors 68030

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    Mar 21, 2014
    Location:
    Portland / Seattle
    #2
    Use a different cable? You did not indicate what interface you're using...
     
  3. Roadking714 thread starter macrumors regular

    Joined:
    Mar 7, 2014
    #3
    I switched from a hdmi to a thunderbolt cable still doing the same thing it's every now and then...i have to reboot in order for it to fix or open and shut the macbook.
     
  4. campyguy macrumors 68030

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #4
    I'll suggest another cable, having also forgotten to ask which rMBP model you're using (my bad). I'll assume that you're using a 4k-compliant rMBP...

    I'll highly recommend switching to a DP 1.2-compliant cable - there's only a few available for sale. I switched my own and my company to Accell mDP-DP cables, purchased them from Amazon (no affiliate links here!). We're using BenQ, Dell, and ASUS 4k displays, and only the Eizo (non-4k) displays in my offices shipped with compliant (not "compatible" as that's a different beast...) cables. They're on the DisplayPort.org web portal.

    Apple's TB 1/2 is DP 1.1a-compliant - not suitable for 4k. I've tested them, personally. You'll see correct EDID data (see below), but the bandwidth is not sufficient for 4k @60Hz.

    Apple's HDMI is 1.4. You'll get 4k, but you won't get the display's EDID information conferred to a Mac or a PC without a 3rd-party hack. Again, I've tried this myself.

    A few days ago, I dropped off a bag of DP and mDP-DP cables at a local geek repository - with lots of 3rd-party cables from reputable manufacturers of cables, lots of "compatible" cables that passed power of Pin 20 (a no-no, the interwebs are saturated with "fixes" for this issue). I've posted here in MR's forums to try Accell display cables - they're compliant and just work. I tried everything, including forking over for 3rd-party licenses of nice utilities - I no longer need any utilities since the cable brand swap.

    Since my opting to swap out for Accell cables, no more games with rebooting/logging out and in/pulling hair out...

    As to the "compliant" vs. "compatible" thing, I'm a tech writer and pick up on subtle nuances in phrasing. Compliant "works", compatible is a marketing pitch for not-compliant products IMHO...
     
  5. Roadking714 thread starter macrumors regular

    Joined:
    Mar 7, 2014
    #5
    I'm using a 15 mid 2014 rmbp with Intel iris pro.. And the cable is a mini displayport thunderbolt 2 to display port 4k resolution ready connected to a lg 27' 4k monitor
     
  6. campyguy macrumors 68030

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #6
    All TB 1/2 cables - are DisplayPort 1.1a compliant. DP 1.1a is a video signal bandwidth bottleneck for newer computers. Get a newer cable, specifically, the brand I'd recommended - most DP cables are listed as "compatible" but they're not compliant; I get went through this myself.

    We have Eizo, Dell, and BenQ displays - about 4 dozen of them - and only the Eizo displays shipped with compliant cables, and they're the only ones that worked as expected. Beyond this bit of advice, I can't help - a $20 cable will pretty much fix this for you...
     
  7. Roadking714 thread starter macrumors regular

    Joined:
    Mar 7, 2014
    #7
    Can you put up a link it will help me a bunch.. appreciate it
     
  8. campyguy macrumors 68030

    Joined:
    Mar 21, 2014
    Location:
    Portland / Seattle
    #8
    Forgive my earlier bit of being tongue-tied in my writing, not much sleep with a friend in hospital and so worried about him and his missus - proofing was a bit down the list of my concerns today...

    The product I alluded to is here:
    http://www.accellcables.com/collect...t-to-displayport-1-2-cable?variant=3258804356

    They're available online in many places - I chose Amazon as I have Prime... The product we're using is P/N B143B-007B, black at 2m in length.

    IMHO, the keys to pay attention to are compliance and throughput. I didn't read the fine print before wasting my money on other cables, and I'll offer that you consider doing just that - I used digital tools to measure current and throughput. Cheers!
     
  9. Roadking714 thread starter macrumors regular

    Joined:
    Mar 7, 2014
    #9
    Thanks I'll look into it
     

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