eGPU and MBP2018 - which graphic card is running?

Discussion in 'MacBook Pro' started by mortenjensen, Dec 17, 2018.

  1. mortenjensen macrumors regular

    Mar 19, 2012
    I have a 580 blackmagic eGPU in for test to see if it helps the somewhat choppy MBP2018 (13'')/LG 5K-combo. It is basically plug'n play, and the card is registered alright in system info.
    But I honestly do NOT find it to improve IU animation (mission control etc.) - so I am wondering if the system only switches to the eGPU under heavy load. How do I know which graphic card I am running on?

    Under the apple logo, the internal GPU is the only one displayed. I also downloaded a GPU test to see if the eGPU is displayed. "GPU-Test mac" will only test the internal card.

    There are seemingly nowhere to force the system to use the eGPU.

    Anyone knows how this works?

  2. leman macrumors G3

    Oct 14, 2008
    Sorry for a dumb question, but you did connect the display to the eGPU?

    Regardless of all this, choppiness of mission control usually isn't because of the slow GPU (an integrated GPU is more than fast enough for this) but because of slow apps... If you look at it in more detail, what mission control is doing is fairly crazy: its drawing ALL the app windows in real-time. Even if one app is coded poorly and can't draw fast enough, you will get lag. Similar for app resizing, as Mac continuously redraws the window during resize, a slow app just won't be able to keep up.
  3. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    I have tried both and here is a funny thing:
    - when the LG is connected directly to the eGPU, the eGPU is listed in "About this Mac" - BUT the resolution is lowered! It looses it retina resolution and goes back to HD.
    - when the LG is connected directly to the Mac, it is not listed in "About..." - but the resolution is retina as it should be.

    In both cases, the eGPU is recognized and an icon is displayed in the top bar.

    So I am wondering what is going on here! In reality, the eGPU makes no difference. Is it only optimized for gaming?

  4. fpenta macrumors member

    Oct 30, 2016

    I was having the same problem with the 15" MPB 2016 with Radeon 460 and LG 5K. Performance was bad in 5k. Bought the Blackmagic eGPU hoping for some smoothness and haven't noticed any changes. It's not optimized for that. Returned it.
    Bought the new MPB 2018 with Vega and performance is amazing, perfectly optimized for 5k.
  5. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    yes, I am afraid that you have to go 15'' in order to have the LG to run smoothly.
    Is it really needed to go all the way with Vega? Is the 580-discrete not enough?

    My problem: I really like the form factor of the 13''. In reality, I would opt for the 12'' had it had the power.
  6. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    It is really weird if this is the way it is - that the Blackmagic simply provides not noticeable performance boost for regular office use.
  7. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    I found this review that more or less settle the issue: Blackmagic's eGPU does NOT deliver, when it comes to regular office use. It is designed to work with specific apps, not to work across the board:

    This is far from what I expected. So it is going back.

  8. chrfr macrumors 604

    Jul 11, 2009
    This is to be expected. "Regular office" apps don't rely on GPU acceleration. They typically barely even tax the CPU anyway.
  9. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    Well, beg to disagree, when you are using the LG 5K monitor. Then there is a lot of lagging, skipped frames in IU animations etc. going on. Actually really surprising!

    In my estimation, you will need a 15'' with internal discrete graphics to run the LG 5K anywhere near something acceptable for regular office use.
  10. Glmnet1 macrumors 6502a

    Oct 21, 2017
    Before you return it I would check the cables. You need to plug the monitor in the eGPU but it sounds like one of your cables doesn't support the 5k resolution. USB C cables can be tricky, they all look the same but have very different capacities.

    Even if it's not optimized for office apps, macOS itself should use it fully.
  11. John-117 macrumors member

    Apr 22, 2010
    This is probably correct.

    The eGPU should be more than capable of driving the 5k UltraFine display. One of your cables might not be either Thunderbolt 3, or is a lemon.
  12. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    The cables I use are the ones that ship with the monitor and the eGPU. it also shows up in the settings.

    I am afraid that there is nothing wrong with anything. Except that it does not work for a general purpose! It is designes for specifik apps. Take the time to read the detailed review I linked to.

    I have a hard time believing this as well
  13. John-117, Dec 18, 2018
    Last edited: Dec 18, 2018

    John-117 macrumors member

    Apr 22, 2010
    That's not what the review claims. Some apps are optimized to utilize an eGPU, but on Mojave you can force any app to utilize it. Also, the eGPU should be able to drive the 5k or 4k UltraFine display without problem.

    Having an internal discrete GPU wouldn't affect performance in any meaningful way for office/productivity apps, so you wouldn't see any change with an eGPU either.

    I would still recommend testing with other cables because of the issues you describe here when the display is connected to the eGPU directly instead of the Mac. I would also go to the display section of System Preferences and hold option for more resolutions.

  14. mortenjensen thread starter macrumors regular

    Mar 19, 2012
    Yes, on Majove, you can "force" apps to use the eGPU - but that is exactly not what you want as a non-gamer or non-specialist working with graphics or the like. You want it to work across the board, to take over the GPU tasks for regular IU-animations to get rid of the nowhere near butter-like experience, when the MBP 2018 13'' runs a LG 5K.

    This is not the case - and it is not stated specifically by Apple as the reviewer notes. For this very reason, he ends up giving it mere two stars.

    This just how it is with the state of development right now. I thought it was otherwise - but luckily, Apple has a great return policy.

    Bottom line: Blackmagic eGPU's are only for specialized purposes, not a generel GPU performance boost.

  15. richinaus macrumors 6502a

    Oct 26, 2014
    Just to add in I will say that the Vega 64 in the imac pro [same display as the 5K LG] makes it run super smooth. It is beyond amazing to me how nice it is, and is by far the best macOS experience I have had on any mac at any time.
    I guess you could buy an eGPU case and a Vega 64 and have a similar experience. Have you had a good look at ?

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