Bandwidth required to drive UW QHD ... + USB3 hub?

Discussion in 'MacBook Pro' started by wegster, Oct 15, 2016.

  1. wegster macrumors 6502

    Nov 1, 2006
    (waiting for JJToft of Samuelson to jump in.. ;) )

    So I'm picking up a UW QHD 34" display, resolution 3440x1440, for my BTO MBP 2011 w/dGPU (1GB RAM AMD 6750M) . The display has Thunderbolt (not mini-DP) ports on it, so I'll be connecting via 'real' TB cable.

    Now, the resolution alone x color/bps isn't astronomical but I'm missing something in calculating true bandwidth required - as the display has a built-in USB3 hub, is there enough bandwidth on a TB1 port to handle both the display AND the USB3 hub, or will it only negotiate as a USB2 hub?

    USB3 is a theoretical 5Gb/sec with TB1 being AFAIK 10Gb/sec, but - anyone?
    It's also true the 2011MBP does NOT have built-in USB3, but I believe you can do a TB -> USB3 hub w/out issues.

    Worst case, the display arrives this week and will report back, but if anyone knows definitively..?
  2. Samuelsan2001 macrumors 604

    Oct 24, 2013
    It should do there is enough bandwidth on thunderbolt 1 to run the display and one USB at USB 3.0 speeds, never tried it myself though. Do report back. :)
  3. wegster thread starter macrumors 6502

    Nov 1, 2006
    Disappointing - $32 for a 'certified' TB cable vs a handful of mini-DP variants I have at work and either both TB ports on the display are bad, or the brand new cable is. Also checked using my wife's late 2013 13" RMBP with that cable; no good there either.

    Had to connect via TB -> Displayport, which will do full 3440x1440, and I did connect the other display via USB w/DP driver to HDMI (1920x1200). Fans are hovering at 6200RPM without much going on, but note this is with the 3440x1440@60Hz, 1920x1200, and the MBP 1680x1050 all going.

    The LGF display is..quite nice so far. The curvature isn't noticeable for the most part without looking for it - some may actually want more curvature to the screen depending on screen placement, as you can tell if one end is slightly closer yo you. The speakers while not a 7.2 or even 5.2 setup definitely are louder than the MBPs and passable with a semblance of actual bass. Note that at least via DP, you can not control the display sound volume directly from the OS X audio controls or preferences.

    Unplugging the USB -> HDMI didn't have an immediate effect nom fan speed, so will see what things are looking like in 30 mins or so - have to get some work done anyways. Will be fairly disappointed if fans remain at max via DP, but will hopefully at least settle down a bit.

    The ScreenSplit software works fairly simply - choose a config (layout, how you'd like to carve up the screen) from 10 or so options (e.g. balanced 50/50 left/right of the 34" display) and when dragging windows around it will highlight the split areas - dropping near the corner (possible anywhere in it) will auto-size that app/window to fit the 'segment.'

    Will hopefully come up with a second TB->TB cable from work tomorrow, or at least TB->mini-DP to check the display input, and hopefully check out if the USB3 hub functions via TB alone.
  4. wegster thread starter macrumors 6502

    Nov 1, 2006
    Just adding - the model I went with is an LG 34UC87M-B which comes with a 3 year advance swap warrantee (vs the 1 year consumer warrantees). There is some backlight bleed, but it's fairly minimal which equates to I've used UIPS panels for years and it doesn't bother me one bit in usage so far...

    The LG Screen Switch software - well, that takes some getting used to. I think I like it, but it takes some thinking as to what your most effective and/or typical app layout should look like, as if for example, you have a full height right hand side and a pair of equal 1/2 height 'segments' on the left hand side, moving any app into any of the areas will maximize the app 'within the segment.' The half height segments will allow you to resize the vertical space and 'adjust' the app(s) in the adjacent segment, but if you move an app into the 'full height' segment and want to make it < full height, it will re-size it back to full height.

    It's not 'bad' and would work great for people commonly using N applications all day in and out, possibly a bit less so when you run a dozen+ apps throughout the day in different combinations. I'll need to see if there are any modifiers on drag/auto-sizing to allow an 'override' or not, and at some other software options to see which fits best. Now, having said that, I can still make it work for my workflow, but a pair of these might be the ticket... e.g. 1x screen divided into quarters and the other into 2x or 2x full height. Thinking about this one though, that would make for a seriously wide display(paid of) and it may actually be too much, depending on if both displays were used for active work vs monitoring. Yep, need to adjust to this big mofo for a bit yet.. ;)
  5. wegster thread starter macrumors 6502

    Nov 1, 2006
    Updating - seems like the first brand-new TB cable was a bad cable.
    Had Amazon send me a OWC cable, mainly as the Apple official cable got mixed reviews on durability.
    New cable showed up today, plugged it into one of the TB ports and up and running at full res/60Hz.

    Brought up sysinfo and it's seeing the built-in USB3 hub, and connecting my Sentey USB3 10 port hub to one of the display USB3 ports and it's all being displayed via the USB section.

    Plugged in my now old OWC 500GB SSD into the hub and ran Blackmagic, and getting pretty much the same throughput I did when it was installed in the laptop via 6Gb/s SATA - 170MB/sec write, 215MB/sec reads.

    So in short, yes, looks like TB1 can drive a UW QHD 3140x1440 display plus use the internal USB3 hub, and now has reduced my cable connection count by one, at least at home. Might be of some use to those not immediately jumping on the new MBPs once released.
  6. photoz macrumors member

    Jun 17, 2006
    @wegster Since you own one of these monitors, can you shed any light on the differences between the 87,88 and 95 variants of the LG 34" monitors? All of them have Thunderbolt options, still can't find any discernable differences in specs other than frame styling.
    thanks for your time.
  7. wegster, Oct 24, 2016
    Last edited: Oct 25, 2016

    wegster thread starter macrumors 6502

    Nov 1, 2006
    Yeah, their model #s are utterly insane if someone's expecting them to be easily deciphered across year/specs, etc. :-/
    UM vs UC = UC is curved, UM is flat.

    UM95 seems to have come out in 2014

    The UM/UC97 seems to be 2015 model, as well as the 34UC/M87 variants

    I THINK these are all 2016 models:
    34UC98 - Curved, 2x Thunderbolt, White Back, Silver Stand
    34UC88 - Curved, no Thunderbolt, all Black
    34UM88-P - Flat, 2x Thunderbolt, all Black
    34UM88C - Flat, no Thunderbolt, all Black

    The UM/UC88 and UC/UM98 have FreeSync, the others do not. (87, 97) - possible that's their encoding, ends in 8 = FreeSync, ends in 7 not? Note that per a random find from an LG rep, the main difference between the UC/M88 and 98 are the same panel, different stands + TB ports or not.

    The last alpha digit, C or M, e.g. as in 34UC87M vs 34UC87C seem to denote C(consumer) = 1yr warrantee vs 3yr (M) commercial/advance swap displays - likely the sam displays but stronger warrantees.

    Yep, it's about as confusing as mud. There have apparently been panel backlight bleed improvements, and I BELIEVE all of the newer ones have both 'reader mode' (basically, blue-light reduction preset modes) and flicker-free for the backlight.

    The above was NOT easy to put together - my notes were incomplete so had to dig a bit, and as it is, I'm unsure if it actually helps, as their models are beyond confusing. Check the curvature radius of each, as they did change at some point (possibly only on ~2K vs 4K models - not positive).

    One cool thing I just saw that I'm not sure applies to all - seems like at least the 87 and I think the 88s can be 'stacked' using the existing stands or with an adapter from LG(e.g. a pair of them, one on top of the other from the existing stand). I may consider this down the line as I'm unsure a pair of them side by side works for me.
  8. photoz macrumors member

    Jun 17, 2006
    Thank you very kindly for that wrap up :)

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7 October 15, 2016