TB3 - TB2 adapter and Displayport

Discussion in 'MacBook Pro' started by superbass, Nov 29, 2016.

  1. superbass macrumors newbie

    Jan 19, 2004
    I'm planning out a Macbook Pro 2016 purchase, and understand that the Apple TB 3 to TB 2 dongle doesn't directly support Displayport.

    What if I'm daisy-chaining the monitor off a TB 2 drive?

    For example - Apple TB3 to TB 2 dongle / Lacie d2 Thunderbolt 2 drive / MiniDisplayport - Displayport cable to my Asus PB277Q monitor?

    Anyone know if this will work? I don't want to tie up one of the ports with just running the monitor.
  2. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    I can't offer a definitive bit of advice, however, after reading the relevant Apple Support document (https://support.apple.com/en-us/HT207266) last week for my own plans, that document does not rule out connecting a DP device on the other end of a TB daisy chain.

    I can offer, however, the results will be less than ideal for my needs so I'm passing on that adapter and ones like it. The ports on older Macs aren't just TB2 - they're also DP 1.2-compliant ports, there's more going on here than calling these ports "Thunderbolt 2". The TB2 spec, however, is relevant to adapters and cables and carries "only" DP 1.1a - *significantly* less bandwidth is available when compared to DP 1.2 and 1.2a and, if Apple sticks to the TB2 spec, the resulting throughput to the display on the other end will be throttled, by design.

    Also, refer to a few of my posts about this to others who were using TB cables to connect the new rMBP to DP 1.2 displays - they didn't even work, given that the displays I was writing about required DP 1.2 and 1.1a did not provide sufficient throughput to drive the displays. I've got over 50 displays in my offices, and all of them require DP 1.2 at a minimum. When connected via a TB cable to a Mac or PC, those displays lagged big time. I suspect that this Apple adapter has those limitations listed because of the DP 1.1a spec. Similar adapters will also likely cause issues in this regard.

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