Considering a cMP, can it drive 2x 4k displays?

Discussion in 'Mac Pro' started by tubular-, Apr 1, 2015.

  1. tubular-, Apr 1, 2015
    Last edited: Apr 1, 2015

    tubular- macrumors newbie

    Apr 1, 2015
    Going to move on from my late '13 15" rMBP to something more powerful. First thought was a refurb nMP but it seems likely it could be upgraded in the next 6 months so waiting til 2nd gen nMP refurbs become available seems like the best option.

    In the meantime, I want something that can drive 2x 4k displays. Knowing nothing about the cMP:

    1 - Can this be done?
    2 - How simple is it? It'll be a work machine so I don't want to deal with changing kexts/having to fiddle with it every time there is a software update
    3 - Rough costs? If its going to be close to $2,500 it makes more sense to just get a refurb now, IMO.

    Assuming I can find one on craigslist, do I flash it, then do ram/cpu upgrades, then gpu?

  2. netkas macrumors 65816

    Oct 2, 2007
    get nvidia 970/980 card and it can driver 2 4k.

    better yet mac edition form mvc, to have 4k bootscreen
  3. Surrat macrumors 6502


    Jun 20, 2014
    United States
    Another advantage of the mvc efi flashed cards is you wont need to worry about OS updates giving you a black screen like can happen with unflashed 970/980.
  4. tubular- thread starter macrumors newbie

    Apr 1, 2015
    How about the Mac Edition 7950s? Are they relatively plug and play? They seem to have 2x mDP, are there any software impediments?

    How much do 4,1 or 5,1 machines go for?
  5. netkas macrumors 65816

    Oct 2, 2007
    I have tried flashed 7950 (with full bios of mac edition, not hybrid), no 4k at all, no bootscreen, no osx support.
  6. Macinsquatch macrumors member

    Mar 28, 2015
    Dual 4K

    It can be done, I have a Mac Pro 5,1 with a 7950 and a 970 in my machine. Had to install an extra power supply in the dvd drive bay but it all works fine and I have a boot screen. Even Windows works fine.
    Running a Dell P2715Q monitor, with the second on the way. I tested 4k on both cards before ordering and both were able to output 4k resolution.
  7. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    A lot depends on exactly which 4K display you use.

    I can now test with a Dell 5K in 4K SST mode and a Asus PQ-321Q which is MST 4K 60Hz. Their behavior is 100% different from each other.

    I think someone once started a thread where people listed which display and GPU and how it behaved. We really need something like that, but it also has to be cross-referenced by OS version and Nvidia driver version.
  8. kennyman macrumors regular

    May 4, 2011
    Just curious, are you able to sleep and wake up the dell monitor on 7950? I have been having issues with endless reboot when I connect P2715Q to a flashed 280X. Have you experienced any of these problems? Thx
  9. Macinsquatch macrumors member

    Mar 28, 2015
    On the 7950 alone yes. But this is a Sapphire mac edition card.
    With both cards the Aux PSU isn't woken up in time to power the 7950 so it reboots due to the 970.
    With the 970 alone in the machine it reboots on sleep, I'm assuming it has something to do with it being a non efi card and not knowing the power state that apple is trying to put it in. So currently system sleep isn't working...yet

    The Dell monitor does turn off when I tell it to turn off in the system prefs and wakes up accordingly. The power light even has a nice slow pulse just like the power light on my mac pro.
  10. AndreeOnline macrumors 6502


    Aug 15, 2014
    On a tangent: I have zero issues with my non flashed MSI 280X driving two Dell 2515H (pretty new 25" 2560x1440px) monitors.
  11. netkas macrumors 65816

    Oct 2, 2007
    Non flashed is fine, because uses generic framebuffer. Flashed is a can of bugs.
  12. ShawnF macrumors regular

    May 10, 2014
    Hi Netkas. So a non-flashed 280X is actually better to use on OSX Mavericks than a flashed 280X?
  13. kennyman, Apr 4, 2015
    Last edited: Apr 4, 2015

    kennyman macrumors regular

    May 4, 2011
    Yes, you are correct. Sapphire 7950 keeps rebooting with mDP to DP when connected to Dell 4K and also on another Dell monitor, same issue (sorry, I cannot remember the exact model, but it was a non-4K monitor at work).

    This is very weird. I had the same problem with a MSI 280X card but I have not experienced any reboot issue with a Gigabyte 7970 EFI flashed. I even tried Futomaki Personality on MSI and still the same issue.

    However after poking around, I have found that Dell monitor might be misbehaving here. I have found few scattered information related to DDC/CI standards. This command interface sends data from computer to monitor, as well as sensor data from monitor to computer.

    If it is implemented correctly, the monitor should be able to wake/boot correctly with proper EDID reading but I do not know what version Dell using and have no info about that on the web. Anyway, I have ended up disabling this function from the dell monitor menu for now. It`s a Dell after all :p

    Good luck with your PSU install, just want to share, I have the same AUX PSU.
  14. tubular- thread starter macrumors newbie

    Apr 1, 2015
    Thanks for the replies guys.

    So it seems while it is doable, the graphics cards are a little touchy even if I were to go with a Sapphire 7950. If that's the case I guess a flashed 280x for half the price is worth the headache?

    I'd likely do the following:

    5,1 single core - $600?
    X5687 - $150
    16 GB RAM - $200
    Flashed 280X or Sapphire 7950 - $500
    PCIe SSD and tray - $300
    Misc - $100

    Roughly $1,850 is creeping up towards a used nMP though. We'll see.
  15. RoastingPig macrumors 68000


    Jul 23, 2012
    get used ebay ram...16gb is about $60 4x4gb

    use any graphics card..flashed is just for convenience of boot screen and other small things..not to much of a big deal.

    i had a flashed 780 that i payed $800 once upon a time. now i have an unflashed 980
  16. Macinsquatch macrumors member

    Mar 28, 2015
    Just for reference, I got my 09 Mac Pro with the dual processor and a 7950 for $1100. Then I flashed it to a 5,1 and swapped the processors out for X5690's for $600. So for $1700 I have a machine with 12 cores @ 3.46GHz. I was also approaching the cost of the low end nMP but it can't touch the performance of this thing. Plus the 970 is relatively cheap and power efficient, makes a great second card.
  17. neomorpheus macrumors regular

    Dec 17, 2014
    Not to stir anything, but it looks like a hackintosh is an easier and better way to run osx on top of the line hardware.
    I'm thinking in selling my cmp 4.1 and going that route.
    I just don't like the idea that the only way I can have this machine functional is by paying MVC for a modded card.
  18. nigelbb macrumors 65816

    Dec 22, 2012
    AIUI your options are either to pay a premium of $400-$500 for a flashed card or pay $120 for a supported Apple graphics card e.g. GT120 to use alongside a regular PC graphics card. How much is a boot screen worth to you?
  19. neomorpheus, Apr 7, 2015
    Last edited: Apr 7, 2015

    neomorpheus macrumors regular

    Dec 17, 2014
    The boot screen is very valuable, especially if you dual or triple boot.

    But you kind of missed my point and I will go a bit off topic here.
    After reading about all the upgrades and hacks needed or useful for cMP, I think that is easier to just set up a hackintosh, instead of fighting over and over with a cMP.

    If you want a new card, with boot screen, you either buy an old one or pay MVC almost 100 (the price of a new vid card for regular hackintosh) or go without it.

    Need to change the BT/WiFi module (not that bad if you are willing to track the parts, which cost around 30 bucks or again, pay up to 100 to MVC)

    Deal with apple crippling your system, just because (software limited options, like what Netkas proved with the soft mod of the 4.1 to 5.1)
    Or limiting 4K refresh to 30mhz, again on software.

    The list goes on and on. So back to my point, if I'm going to struggle this much, might as well get faster, newer hardware and go the hackintosh way.

    Sorry for the rant and going off topic.
  20. Macinsquatch, Apr 7, 2015
    Last edited: Apr 8, 2015

    Macinsquatch macrumors member

    Mar 28, 2015
    Got the Daul 4k setup running without issues.

    A Hackintosh will be a labor of love. Just as modifying a cMP. I am assuming that at some point we will see a method to flash the 900 series cards, until then I'm going to run my dual card setup. Only mod I had to do was install a $40 aux psu in the unused second dvd bay.


    Update: Currently everything is working as it should. Monitor sleep is working fine, computer sleep is working perfect. These Dell monitors are amazingly clear.

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