Dismal performance with 3 monitors

Discussion in 'MacBook Pro' started by mfaughn, Jun 28, 2016.

  1. mfaughn macrumors newbie

    mfaughn

    Joined:
    May 24, 2012
    #1
    I am a developer and have been trying to use my rMBP (specs in attached png) with three external monitors (with the lid closed). The monitors are two Dell 1920x1200 monitors and a Dell 4K monitor scaled to 2560x1440. I was previously using tw0 2560x1440 (one Apple, one HP) monitors and one of the aforesaid 1920x1200 monitors. In both cases I experience drastic degradation of the OS performance. Everything gets really slow - from mission control to web page loading. As soon as I drop back to using just two monitors (doesn't matter which two) then everything seems fine again. I do happen to have a lot of desktops going (~8-10) and often have a lot of application windows open. I was just curious if this behavior is typical. Has anyone experimented and discovered any more specific parameters that make this behavior any better or worse? I really like having the display real estate but not if it is going to send my computer into a stupor. I'm wondering if it would be alright I replaced the two 1920x1200 units with a single 2560x1440 or even a 3440x1440?
     
  2. Brandon0448 macrumors 6502

    Brandon0448

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    #2
    You are simply asking too much out of your little rMBP, while they are pretty powerful machines that amount of screen real state is crossing into desktop territory with a powerful dedicated graphics chip. That is a lot of pixels for a laptop to drive, especially if you have a model with integrated graphics. I am not familiar with how many pixels these laptops can run but it is pretty obvious you have exceeded it.

    Two 1920x1200 monitors would be about 4.6 million pixels total, one 2560x1440 monitor would be bit little less at about 3.7 million pixels and one 3440x1440 monitor would be even more at about 5 million pixels. Replacing the two monitors with the 2560x1440 monitor would give you a little better performance but not by much. Replacing the two monitors with the 3440x1440 monitor would give you even worse performance.

    You could try using two 2560x1440 monitors but I can't guarantee that it will work because I have no first hand experience using multiple external monitors with these rMBPs, it would certainly run a little better than your current three monitor setup. I have a triple 1920x1200 monitor setup for my desk at home but they are being run by a custom build desktop computer with a powerful dedicated graphics chip.

    My recommendation if you want to run that many screens would be to get a desktop computer with a decent dedicated graphics chip that is capable of driving that many pixels. If you are using a rMBP with integrated graphics then the 15" rMBP with dedicated graphics would probably be able to run the three screens but I would still recommend a dedicated desktop as there is no point in having a laptop if you don't want to carry it around. It would be much cheaper to go with a Windows machine because Apple charges an arm and a leg for their Mac Pros.

    Good luck, if you would like help picking out a desktop that is capable of driving that many pixels I would gladly help give you a second opinion. It is a shame to have a nice 4k monitor only to scale back the resolution because your current computer is unable to drive it.
     
  3. BrianBaughn macrumors 601

    BrianBaughn

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    #3
    One man's "Dismal" is another man's "Holy smokes! Can it really do that?"
     
  4. mfaughn thread starter macrumors newbie

    mfaughn

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    May 24, 2012
    #4
    Hmmm, I am running the 4K (at 2560x1440), one 1920x1200, and the rMBP open (at 'looks like 1440x900) right now with no real trouble. That is 7.3M total pixels vs 8.3M total pixels for the setup that I am having problems with. There are reports of people successfully running three external monitors from 15" rMBP but also reported differences in capabilities within that class of machine. I will say that in all cases, adding that third monitor results in the fan speed kicking up noticeably.

    I'm not scaling back the resolution on the 4K because the rMBP can't drive it but because my eyesight simply isn't good enough to see text at 4K. I have a 4K because that is what the boss bought me.

    Anyhow, a desktop is a non-starter. I have to be mobile. I could migrate to Linux but it would be a painful productivity hit at this point. Windows? I can't think of anything nice to say.

    I'm going to try and borrow a 2K monitor and mix that in in different ways and see what works.

    edit: I guess this answers a lot of questions => http://www.everymac.com/systems/app...-display-how-to-manually-switch-graphics.html
    I have a mid-2014 with Iris Pro 5200 & GeForce GT 750M*. I can't actually find a situation where it reports that it is actually using the Iris Pro at all, even with just the built-in screen running by itself.

     
  5. jerryk macrumors 68020

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    SF Bay Area
    #5
    How are you connecting these 3 monitors? If I use the USB to connect a monitor my system's performance drops like a stone. However with 2 DP monitors it is fine. I haven't tried the HDMI, but suspect that will be laggy because of the slow refresh rate (30Hz) at 4K
     
  6. mfaughn thread starter macrumors newbie

    mfaughn

    Joined:
    May 24, 2012
    #6
    4K is always through DP. The others are DP and HDMI. It seems to handle a second monitor just fine regardless of whether it is through DP or HDMI. It is only when I have two on DP and one on HDMI that I have problems. I installed cscreen today in hopes that I could lower the refresh rate on the 4K monitor (which ought to reduce the load on the GPU). cscreen will tell you all of the available combinations for resolution and refresh rate for (some) monitors and apparently there is no option for me to run at 2560x1440 with anything other than a 60Hz referesh rate. Instructive but ultimately a bust.

    I am fairly certain that HDMI will handle 1920x1200 at higher than 30Hz. El Cap figures you don't need to know what the refresh rate is unless you are actually hooked up to a TV (in my limited experience), so it is hard to say. It depends on the implementation (both hardware and OS). At any rate, I use my displays for writing code so 30Hz would be acceptable. In general, it seems that running at a lower refresh rate should reduce lag since there is a lower processing burden. You may lose some picture quality when gaming or watching movies but that is a different issue.

     
  7. slayerizer macrumors 6502a

    slayerizer

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    Nov 9, 2012
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    Canada
    #7
    I use a maxed out rMBP 2013 (with dedicated gpu, 512gb ssd) and it's very slow for me too. I use the laptop display + 4k and it's OK for light task only (web surfing, Office). Silly me, I even tried to play a 4k video I downloaded and barely got 5 fps. The 4k will probably be going back on my PC.
     
  8. jerryk macrumors 68020

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    SF Bay Area
    #8
    Here is what Apple says about it. https://support.apple.com/en-us/HT206587 Check the HDMI section. HDMI is a TV interface.

    But you are correct, for coding refresh rate does not matter.

    I develop all day long and am considering getting 2-4K monitors or a single 43+ inch Ultrawide. The Ultrawides can be segmenting to have separate display windows, at least on Windows. I currently run 2-24 inch 1920X1080s on both my Mac and Windows systems
     
  9. Brandon0448 macrumors 6502

    Brandon0448

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    #9
    Don't quote me on this but if I remember correctly the rMBP with dedicated graphics can only power external displays with the dedicated chip, where with the internal display it can be powered by either the integrated or dedicated graphics chip. So I'm assuming with your two external monitor setup and one internal monitor it is spreading the load across both graphics drivers which leads to much better performance. But with three external monitors they must all be driven by the dedicated graphics chip.

    Having a desktop and being mobile are not mutually exclusive, you can simply sync your work across your devices. I'm am not sure what you are working with but github or bitbucket are the first that come to my mind. It sounds like this is for work so you might be able to talk your boss into getting you a Mac Pro, switching to Linux would most likely cause the performance to degrade even more as Linux never has decent graphics drivers with modern hardware. The cheapest (new) Mac Pro you can buy right now is $3000 but it would easily drive three 4k or 5k displays at their native resolution.

    Have you tried scaling the text on the 4k display while at its native resolution? OS X has the best text scaling I have seen in any OS and you should be able to get it to a readable size. Then you would get the clarity of the 4k display while still maintaining a usable text size. But that certainly wont help you with the performance issues you are having while trying to drive it with your rMBP. I just want you to be able to be able to get the most out of your monitors.
     
  10. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #10
    It's a thin light laptop the fact that it can run more than one screen when you have one that is a 4K is amazing, as others have said if you want a multiple screen set up with 4 k monitors a desktop is the answer.

    And yes all the external screens are connected to the dGPU so that is running them all its not bad but you are expecting a bit much from a mobile graphics chip from 3 years ago.
     
  11. nStyle macrumors 65816

    Joined:
    Dec 6, 2009
    #11
    Don't know which laptop you have - I guess your specs got deleted, but you've obviously just found the limitations of your machine. There isn't anything special you can do apart from upgrading.
     
  12. Achiever macrumors 6502

    Achiever

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    Jan 23, 2008
    #12
    This seems like a good place to post this question. I have a 13" rMBP 2015, 3.1 ghz i7 with Iris 6100 graphics. I want to use it to drive multiple external displays and since Apple hasn't yet released a 5K display, I have ordered a Dell 4K to use. (This one for reference: https://www.amazon.com/Dell-Monitor...e=UTF8&qid=1468350617&sr=8-1&keywords=dell+4k).

    I am pretty confident I can simply use the external monitor as a second display along with the running rMPB. My question is can I use this computer to drive 2 of those 4K monitors OR, even better, 2 of those 4K external monitors plus the rMPB as a third screen? In either case, how would I hook those up? I can't daisy chain (at least I don't think I can), but can I use the DP from the rMPB to the first screen then something else from the first to the second?

    Has anyone used this rMBP to drive external 4K monitors? Any issues or concerns? Thanks in advance.
     
  13. jerryk macrumors 68020

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    Nov 3, 2011
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    SF Bay Area
    #13
    I believe there is a limitation of 1-4k on the 2015 13" rMBP (the earlier model would not even do a single 4k). Only the 2015 15" rMBP with dGPU can run 2-4K monitors at 60 Hz.

    See, https://support.apple.com/en-us/HT206587

    DP or mini-DP needed.
     
  14. tubeexperience macrumors 68030

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    Feb 17, 2016
    #14
    ...good time to build a Hackintosh with a Geforce GTX 980 Ti or with a Geforce Titan X
     
  15. jerryk macrumors 68020

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    SF Bay Area
    #15
    980 is obsolete. 1080 2 times as fast on 1/3 the power at near the same price. I wish I would waited for the 1070 instead of the 970 I bought a few months ago.
     
  16. tubeexperience macrumors 68030

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    #16
    GTX 1080 is not compatible with OS X.
     
  17. Achiever macrumors 6502

    Achiever

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    #17
    Thanks for the reply, but the plot thickens. The Support thread you linked backs up your assertion, however, the Tech Specs for the MBP suggest that it can power 2 at 4K resolution. http://www.apple.com/macbook-pro/specs-retina/ Anyone have any thoughts or, more importantly, experience trying to drive 2 (or 3 with the internal device) 4kKs from a 13" rMBP?
     
  18. jerryk, Jul 13, 2016
    Last edited: Jul 13, 2016

    jerryk macrumors 68020

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    #18
    Of course. Once again OSX is behind the curve. Damn walled garden.
    --- Post Merged, Jul 13, 2016 ---
    Don't you love it when one part of the company disagrees with the other. Anyway, you should post on the Apple support forums and see if anyone there has tried two 4K monitors.
     
  19. shoehornhands macrumors regular

    Joined:
    Oct 9, 2014
    #19
    Try running the 4k display at 1920x1080, or the native 3840x2160 (i.e. a whole number ratio of the native resolution). 2560x1440 isn't a clean ratio of the native resolution, so the output for each pixel must be calculated (you obviously can't set half of a pixel to once color, and the other half to another). This can potentially impact performance quite a bit.

    If that doesn't help, as others have mentioned, it might just be a bit too much for the computer.

    I'd recommend looking into the 34" 3440x1440 displays. I've been using the curved dell 34" for awhile now, and I've found that I much prefer a single 3440x1440 display over a pair of 1920x1200 displays. You could even run a pair of 3440x1440 displays without issue.

    LG recently released this curved 34" thunderbolt display, which is an awesome option for Mac users (it was designed for Mac, so it's like an up-to-date Apple thunderbolt display):

    http://www.lg.com/us/monitors/lg-34UC98-W-ultrawide-monitor

    If you scroll down the page a bit, you can see 2 of them side-by-side. A pair of curved 34" displays would be the ultimate productivity setup.
     
  20. jerryk macrumors 68020

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    SF Bay Area
    #20
    Here is a video from some guy that tried this with a 13 rMBP. He got 2 4K monitors working and the rMBP display. But, the refresh rate on the 4K monitors was 30 Hz and pretty jerky. He said he got a 15 rMBP instead, but never shows using the 4K monitors on that system.

    https://www.youtube.com/results?search_query=macbook+pro+4k+monitor
     
  21. brand, Jul 14, 2016
    Last edited: Jul 14, 2016

    brand macrumors 601

    brand

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    #21
    Mac OS is not walled garden. Just because an OS does have native support for a certain piece of hardware does not make it a walled garden.
     
  22. Achiever macrumors 6502

    Achiever

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    #22
    Thanks, that is an interesting video. I would note it was posted in July 2014, so the computers he is using are at least one version behind on graphics (and that is assuming they were 2014 models). I am starting to feel better about at least getting dual 4Ks off of this thing. The rMBP as a 3rd monitor would be gravy.

    How would you suggest setting up the 2 4Ks? A mini DP from each of my Thunderbolt ports, 1 into each external?
     
  23. RoboWarriorSr macrumors 6502a

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    Feb 23, 2013
    #23
    Actually it doesn't really suggest it at all but I can see where the misconception lies.

    • Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors.
    It's phrased as "up to 3840 by 2160 (4K) on up to two external displays". From what I read, it suggest a maximum of two displays with resolution UP to 4K. It seems Apple is really banking on the "up to" to mean any resolution to 4K. Its annoying marketing speak. Hardware wise, I'm pretty sure Intel Ark has listed that the Iris 6100 can only support 1 4K display due to bandwidth (hardware wise, it wouldn't be smooth as well).
     
  24. Freyqq, Jul 15, 2016
    Last edited: Jul 15, 2016

    Freyqq macrumors 68040

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    Dec 13, 2004
    #24
    Is it laggy as in low refresh rate or laggy as in jerky/low fps?

    My old setup, with the same laptop as you (15" with 750M), was:
    internal monitor
    2 1920x1200
    1 1280x1024

    So, I was running 11,102,720 pixels. Worked fine, no lag with a few windows open on each on 10.11.

    Now I run just 1 4k and the internal screen, and that works fine too.
     
  25. jerryk macrumors 68020

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    Nov 3, 2011
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    SF Bay Area
    #25
    I run my monitors on the separate mini display ports on my 2015 15 rMBP with dGPU. But mine are not 4K. But, no matter, I prefer to split the bandwidth required between the two display ports.

    Since I program I am contemplating a 4K, but not sure I can read the text if it gets any smaller than on a 1920 X 1200 display. I guess the 4K would make the text sharper at 1920 X 1200, like the retina screen. However, am also looking at at the 34 inch curved Samsung.
     

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