Can the 15 rMBP support 2 4k monitors at 60 hz? Meaning, no lag/beach balls, etc...

Discussion in 'MacBook Pro' started by cmm, Jan 25, 2015.

  1. cmm macrumors 6502a

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    #1
    Will it support it without a discrete GPU, or should I get the 15 rMBP with the discrete GPU? Will there be any lag, like can be found on the 5k iMac with another screen? (I've even read that the 5k iMac GPU is so underpowered it lags while using Mission Control when no external screen is hooked up)

    I was looking at getting dual 24” Dell 4k IPS 60hz screens and either running them at native resolution or 1080p (HiDPi mode). Does it matter, performance-wise, if I run at HiDPI (1080p) or the full 4k resolution?

    If it will lag, what about just one 24” Dell 4k ISP monitor, would that lag? (Assume I am using the rMBP screen as well).

    What about one 32” 4k IPS 60hz screen (e.g., BenQ or Dell), and one 24” 4k IPS 60hz screen? Will my 15 rMBP lag while using the laptop screen, or with the laptop screen closed?

    If there is going to be lag, beach balls, etc, please just tell me and I’ll cave and buy a a Mac Pro. I can’t deal with lagging issues, despite much preferring the portability of a laptop… :(

    I REALLY, REALLY want the portability of a laptop, but the most important thing is no lag!
     
  2. Freyqq, Jan 25, 2015
    Last edited: Jan 25, 2015

    Freyqq macrumors 68040

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    #2
    The 15 with 750M can do:
    1 4k at 60hz over thunderbolt
    1 4k at 30 hz over hdmi (or a 2k screen at 60hz)
    Internal screen

    All at the same time. Lag depends on what you are doing with it.

    If you want 2 4k monitors at 60hz, you need a mac pro. If you want the least lag, get a mac pro. If you really want a laptop, consider getting nice, premium screens that aren't 4k or settling with one monitor that is only at 30hz.
     
  3. cmm thread starter macrumors 6502a

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    #3
    Is lag worse on the rMBP with 750M or the 5k iMac with a second 4k 60hz screen?

     
  4. Freyqq macrumors 68040

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    #4
    Well, the iMac has a more powerful CPU and gpu, so I'd assume the iMac has better performance. The mac pro would have the best, especially if you upgrade the gpus.

    Lag depends on so many factors. You mean interface lag?
     
  5. cmm thread starter macrumors 6502a

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    #5
    I find I swap a lot with 8GB of ram, and I usually have about 15-20 windows open at one time, and between swapping and all the windows, I beachball randomly, and things aren't always click-done. It's very annoying. I really would like to keep my primary machine as a desktop and not have to get a laptop AND a desktop, so I am trying very hard to sell myself on the 15 rMBP rather than going to the 5k iMac (which seems to have the same problems, given the substandard GPU) or a Mac Pro.

    The only benefit of the Mac Pro is 3 4k monitors, instead of 2 total if I used the 5k iMac (yes one monitor would be 4k), or 2 4k externals with the rMBP albeit one would be 30 hz, which is unusable so not even worth considering :( Trying to think if I can get by with just one 4k external monitor since I could use the 15 rMBP screen at the same time, but given I want to run it at retina HiDPi mode, that's only 1920x1080, which just isn't enough screen real estate for me (basically it allows IRC and mail on the MBP screen and an IDE and a PDF open on the external).

    Now if I could get another 5k screen for a decent price, that the 15 rMBP could power, then maybe that would work. But the only way to get 5k is to get a 5k iMac more or less.

    Any comments would be appreciated.Thanks
     
  6. Freyqq macrumors 68040

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    #6
    In my experience, interface lag occurs when you hit a bottleneck - like run out of ram or vram. Alternatively, it happens if osx drivers are not optimized well by apple.
     
  7. cmm thread starter macrumors 6502a

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    #7
    I thought I read that the 15 rMBP can support on 4k 60hz screen and a 52hz screen... is that true?
     
  8. thekev macrumors 604

    thekev

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    #8
    There aren't any that run at 52 hz. You might be thinking of 30 hz, but I don't know whether the macbook pro can run run that. 2013 and newer should be able to drive 4K at 60hz. Also I think the lag is more an issue of drivers and bandwidth than the processing power of that gpu.
     
  9. ygys macrumors member

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    Dec 31, 2014
    #9
    and what about the 13" retina MBP ? can it drive at least one 4K monitor at 60hz ?

    and what about one 4K monitor and one 2K ? (1440p)
     
  10. yjchua95 macrumors 604

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    #10
    The 13" rMBP cannot drive 4K at 60Hz, because of Haswell-U's hardware limitations.

    The most it can do is 4K at 52Hz, and even that requires quite some troublesome tweaking.
     
  11. Samuelsan2001 macrumors 603

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    #11
    To be honest you need a desktop for what you want..

    Laptops just aren't quite there yet for what you want to do. Therefore you have choices to make

    1 Buy the best laptop available and use at a lower functionality than you would like.

    2 Buy a destop with the functionality (probably dual graphics cards) that you want and use something smaller and cheaper for portable computing.

    3 wait until what you want is available.

    I had a look to see if any of the thunderbolt docks could help you but they will only run 1 4 K screen at a time.

    I also had a look at retina imac with 4K external, this has some interesting notes on performance.

    http://barefeats.com/imac5k9.html
     
  12. cmm thread starter macrumors 6502a

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    #12
    I know but I really don't want to have to keep two computers in sync. Right now I am thinking I'll buy a 15 rMBP with discrete GPU and hope for the best when running two 4k monitors off of it. If that fails, I'll have to do more soul searching and hope I can deal with having to keep two computers in sync.

    I read that page before. Not sure if writing code and viewing a bunch of PDFs and other text docs are considered "GPU intensive activity"? That's basically what I do. I have a D70 and load pictures into iPhoto and sometimes edit them in Photoshop but not more than 1 hour per month. I don't play games. I watch youtube videos and sometimes an mkv from my NAS when I'm too lazy to go to the living room to watch on my TV.

    Again, the main reason for trying to stick with a retina MacBookPro is, while I spend 80% of my time stationary, I do need portability 20% of the time, and I don't want to worry about filings not being in sync on my laptop when I need to run out...
     
  13. thekev macrumors 604

    thekev

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    #13
    None of that puts much more strain on your gpu than simply refreshing the dekstop. If you experience lag it may not be the speed of the gpu itself. That's the problem. If it's a bottleneck elsewhere, it doesn't matter what gpu is in the thing. It will be displayport 1.3 before 5K is supported by a general standard (which supports up to 8K).
     
  14. larrysing1963 macrumors regular

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    Aug 16, 2014
    #14
    I'm still not certain you can't get dual 4K @ 60Hz from a retina MBP. I'd love for someone to try it and report back one way or another.

    Maybe the choice of a 34" widescreen and a 4K monitor is the perfect setup for that computer, because you CAN get dual 60Hz out of those two monitors.

    Or alternately, you could buy the two 4K monitors and run one of them @ 3440x1440 using SwitchResX.
     
  15. Samuelsan2001, Jan 28, 2015
    Last edited: Jan 28, 2015

    Samuelsan2001 macrumors 603

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    #15
    Why 4K for that use case??


    you can't but if you aren't running 4K video then it'll be a lot cheaper easier and just as good to go with some decent well calibrated 1440 or 1600 monitors.

    What you do just doesn't require 4K screens I can't see it being a problem if you only get 30hz either with that use case, it's not as though you need anything too fast unless you are editing 4K action on it or gaming.

    I assumed as you were hell bent on 4K @ 60hz that you had a need for it!!!!

    As for syncing between an imac and a laptop you can just VPN into any PC and get what you need if you have internet.
     
  16. zeppo2, Jan 28, 2015
    Last edited: Jan 28, 2015

    zeppo2 macrumors member

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    #16
    Here's a lengthy thread which includes a lot of discussion about the external monitor capabilities of retina macbook pros. I ended up getting the 13" low end rMBP, with hopes that SwitchResX will allow me to power a "4k" monitor such as the P2715Q, if I end up choosing that. So far I haven't even turned on the laptop as I just got it yesterday. i only got 8MB of memory, but I won't be doing any photoshop on it, just coding and of course, around the house for safari surfing, netflix, and youtube would be nice.
     
  17. Freyqq macrumors 68040

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    Dec 13, 2004
    #17
    It might be possible to run 2 monitors at 4k at 50hz over mini-displayport on the 15" rmbp. Never heard of anyone trying this, but it is theoretically possible. You would need a third party program to set the monitors up like this though.
     

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