4K Ultrafine not enough charging power for MacBook 15"

Discussion in 'Mac Accessories' started by tslays, Feb 18, 2017.

  1. tslays macrumors newbie

    tslays

    Joined:
    Feb 18, 2017
    #1
    I have a 2016 Touchbar 15" MBP and have just gotten the 5K Ultrafine for work.

    Now I am looking for a personal monitor and would be in the market for the 4K Ultrafine. But I read the following on an Apple support site: https://support.apple.com/en-us/HT207447

    The UltraFine 4K won't fully power a MacBook Pro (15-inch, 2016), which requires 85W. If you try to charge your 15-inch MacBook Pro through the display, your notebook's battery will be utilized as well. To fully power your MacBook Pro and charge its battery, connect your 15-inch MacBook Pro to its Apple 87W USB-C power adapter when you use it with the UltraFine 4K.

    My question is, will this negatively affect the MBPs battery even when it is plugged to the 4K Ultrafine? I mean, I didn't see any USB-C TB3 Display that can charge the battery of the MBP 15" with more than 60W except the 5K Ultrafine.

    Any thoughts on this? Any recommendations for alternatives?
     
  2. Cougarcat macrumors 604

    Joined:
    Sep 19, 2003
    #2
    You'd need either a Thunderbolt Display or 85W Thunderbolt dock to get full charging. But it will charge at 60 as long as you aren't pushing the system hard.
     
  3. tslays thread starter macrumors newbie

    tslays

    Joined:
    Feb 18, 2017
    #3
    Sometimes I play some games and do some music production. Therefore, there will be times when I push the system above 60w constantly.

    I don't really want a dock because I go USB-C all the way and having the monitor as a hub was one of my main reasons doing so. It is however a valid alternative.

    What TB display would you suggest that delivers 85w or more and is not the 5K Ultrafine?
     
  4. Cougarcat macrumors 604

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    Sep 19, 2003
    #4
    AFAIK the Ultrafine is the only one.

    I've gone with a 4K Dell P2415Q, which I will pair with a Caldigit TB3 dock when it gets released next month.
     
  5. MrX8503 macrumors 68020

    Joined:
    Sep 19, 2010
    #5
    According to MKBHD, the LG 5K can't charge it at 85w even though it's advertised as being able to.

    AFAIK, there isn't a product out there that has proven itself to charge a MBP at a full 85w except for the power brick itself. The Caldigit is advertised to provide 85w, but that hasn't been proven.

    The TB3 spec allows for 100w and 40Gbps of data. So far there's no product/cable that is capable of this. Apple's cable can provide 85w, but at USB2 speeds. The T3 cables on the market are 60w at 40Gbps. It's quite frustrating that a standard doesn't adhere to standard specs. It's kind of the Wild West when it comes to USB-C cables.
     
  6. tslays thread starter macrumors newbie

    tslays

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    Feb 18, 2017
    #6
    Wow, thanks for this information. I really didn't know that the situation is more complicated than I thought...

    I think I will just go with a 60w display and use the power brick when I play a game occasionally. :)

    Does anyone know what kind of tasks or CPU usage push the MBP over 60w power usage? Is it like full usage or more like 70%-80%?
     
  7. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #7
    In theory, in the 15" model the CPU alone can consume up to 45W and the AMD graphics chip can consume a further 35W. These are theoretical maximums and in reality neither will consume that figure due to physical constraints, for example heat, and practical constraints, for example that it is unlikely both chips will be pushed to 100% constantly (especially simultaneously).

    However, that is still 80W peak. Even assuming for argument's sake that it only actually draws an average 70W at peak due to the above factors, the power drawn by the rest of the system - especially the screen if it's at high brightness - can mean the battery drains faster than the power supply can replenish it.

    For recent Macs, this seems to be handled as follows:
    • If the battery is charged, the power supply is connected, and there are no bottlenecks (e.g. overheating), the Mac will run at full performance by drawing power from both the battery and the power supply, i.e. for a total of more than 87W of power.
    • If the battery is close to being drained, the system will throttle down to ensure it uses no more than 87W of power.
    In Windows via Boot Camp (e.g. for gaming) it is likely that this behaviour is not so well-refined as in macOS however.

    But in general, you shouldn't worry about it if you use the 87W power brick when gaming as you suggested.

    (Re MKBHD's complaint at his 5K not providing 85W - I would take it with a pinch of salt: it's an isolated report, and he was provided with pre-production units(s) which may have been defective in this regard.)
     
  8. tslays thread starter macrumors newbie

    tslays

    Joined:
    Feb 18, 2017
    #8
    I actually never thought about the fact that the system might drain more than the power brick can supply. I never experienced a drained battery because of extensive gaming.

    I am doing a lot of Logic music production. I guess this will not use the GPU, therefore I should be fine with the 60w right?

    This really just seems an issue for situations where the GPU is used.
     
  9. Brookzy macrumors 601

    Brookzy

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    UK
    #9
    Logic will be totally fine. The only case I can think of where it would be an issue is processing huge files like MKBHD was, which is unique in that it is constant 100% utilisation, and potentially hours at a time.
     
  10. MrX8503 macrumors 68020

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    Sep 19, 2010
    #10
    I don't know how the charging logic works. Does the power brick override the monitor when charging?
     
  11. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #11
    Yes, the 2016 MacBook Pros choose the best power supply regardless of the order they were connected. So, on a 15" Pro, you can connect an UltraFine 4K to one port and an 87W power adapter to the other and the 87W one will be used.
     
  12. athletejmv macrumors member

    Joined:
    Mar 19, 2011
    #12
    I'm running the 4k with the late 2016 MBP. No issues with keeping a charge here. However, I only use iMovie in regards to intensive applications. Everything else is more school related in regards to productivity... well, there's flash content and media consumption as well. I have the base 15" with the 1TB drive (cost about $3.1k after tax and a student discount of $200, what a joke... but I'm a sucker enough to have bought one lol).

    As far as draining the battery under a full load, if anything that should be good for your battery if you leave your laptop hooked up frequently and use it mostly as a desktop IMO.

    I had the revised 5k (February 2017) with extra shielding, but I didn't like the hues of green and pink on white backgrounds. I'm very finicky about this kind of stuff. The 4k has it too, but way less obvious. I also like that the 4k wobbles considerably less on the desk, the boards looks nicer and it doesn't have a fan humming away (the fan is located behind the mounting plate on the 5k. I have noticed a fan on the 4k and I did look/listen for one.

    In regards to the limited bandwidth on the monitors USC connectors, I use an external HD for storage, laser printer, webcam (the 4k lacks one; 5k is built in) and a lightning cable. For regular external HD file storage, I don't really need anything high-bandwidth.

    I hope this all helped in some way.
     

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