10.9.3 - Dual monitors and clamshell mode no longer working

Discussion in 'OS X Mavericks (10.9)' started by jsh, May 15, 2014.

  1. jsh macrumors regular

    Aug 25, 2008
    My setup:

    Late 2013 rMBP 15" w/ NVIDIA 750M clamshell mode
    Apple Thunderbolt Display @ best for display
    Dell UP2414Q (MiniDisplay Port, running on DisplayPort 1.2) @ best for display

    On 10.9.2, I could use both monitors.

    Since upgrading to 10.9.3, I can only use the Thunderbolt Display OR Dell UP2414Q. I cannot use both at the same time. I've verified this behavior by:

    1) Plugging in both displays
    2) Unplugging the Dell - the Thunderbolt Display becomes active.
    3) Plugging in the Dell and unplugging the Thunderbolt Display - Dell becomes active

    (No reboots/logouts occurred between the steps, and I've verified that both Thunderbolt ports are working.)

    I've already tried reseting the NVRAM and SMC.

    Any ideas?
  2. travishill macrumors regular

    Jan 6, 2004
    In 10.9.2 I'm guessing you weren't pushing the full 4k @ 60hz over DP1.2, and you are now. Full 4k @ 60hz in 10.9.3 is likely taking up all the available display bandwidth.

    Likely you can choose between running at DP1.1 (30hz) like you were in 10.9.2 and have enough bandwidth to run both, or only the 4k at DP1.2 (60hz) which is now available in 10.9.3 (but takes double the display bandwidth, of course).
  3. jsh thread starter macrumors regular

    Aug 25, 2008
    Thanks Travis. That was it! Didn't even consider the bandwidth.

  4. codercotton macrumors newbie

    Dec 6, 2009
    I'm interested in getting the UP2414Q to use with my 2013 rMBP as well, and have a couple of questions...

    1. Does the internal display work with the UP2414Q using MST at 60hz?
    2. Can the the HDMI push another monitor? Either clamshell along with the UP2414Q (@60Hz) or all three displays, UP2414Q+internal+hdmi?


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