12 Replies Latest reply: Feb 12, 2013 10:12 AM by Grant Bennet-Alder
OxygenStudio Level 1 Level 1 (0 points)

Hi all,


I've been having some major problems doing what I thought would be relatively simple.


I have a mac pro 1,1, with a Radeon HD 5770 (Firmware Flashed card, with official apple firmware). What I'm trying to achieve is to have 2 separate displays, and a third that is a duplicate of one of them.


With my other mac pro set up I have achieved this simply by using an external HDMI splitter to duplicate one of the screens. Works perfectly. The problem with my second mac is: I have 2 x 27" screens running at 2560 x 1440 resolution and the 3rd screen which needs to show the duplicated display is only 1080 HD compatible.


I found a DVI splitter box from LINDY that handles 2560 x 1440 resolution and my intension was to simply reduce the resolution of the larger screen down to 1080 so it would run on both monitors. No such luck.


Even with the lower res setting on the 27" screens, the smaller screen keeps saying the signal is "out of range".


As this 3rd screen would only be used now and then I can't justify the cost of buying another 2560 x 1440 montior for this.


Can anyone suggest another way to simply duplicate one of the screens? I need relatively frame accurate signal on the duplicated screen as well.


I've tried a lot of different combinations of cables, adapters, splitters etc. I even tried an HDMI (1,4 standard) splitter which claims to be able to carry 2560 x 1440 resolutions, but the screen still said the signal was out of range.


Any help would be great!





  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)

    The 5770 is capable of supporting three displays if you do everything right. You can Extend the Desktop and/or Mirror the displays in any combination.


    When you Mirror Displays, they WILL be set to EXACTLY the same resolution, no negotiation on that issue.


    The issue with three displays is that the signals provided by Mini DisplayPort through a converter are correct polarity and timing, but not a high enough Voltage for reliable operation unless you use an adapter labeled as ACTIVE to boost up the signal level.


    Single-Link DVI adapters are good for up through 1920 wide. Third-party ACTIVE adapters cost about US$35.


    Above 1920 wide, you need to use Dual-Link DVI ACTIVE adapters, and these have doubled data lines which require even more boost power. These often include a USB lead to pick up power from a USB port. Dual-Link DVI ACTIVE adapters, like the Apple adapter, cost about US$100.


    Arrange Window screenshot.png


    When you have three displays, you can mirror a display by dragging and dropping its screen-area on top of the screen you want it to replicate. The resolutions of both displays will be reset to the highest they can BOTH implement.



  • OxygenStudio Level 1 Level 1 (0 points)

    HI Grant, thanks for the answer.


    I suppose using a Flashed firmware card will throw some variables into the situation ? for example, my card has 2 dual link DVI ports,1 HDMI and 1 Displayport.


    I couldn't get the Displayport output to work with my HPZR2740w monitor for some reason. I'm guessing it's the firmware?


    I did manage to mirror 2 screens and have 1 separate screen before, but that was by installing a 7300 GT card along side my 5770 and using one of it's DVI outputs as a 3rd screen, but unfortunately the performance of the duplicated screen was too slow for my needs (Pro Tools).


    I guess what I'm trying to find out is if I buy an official Apple 5770 whether it will also suffer from low performance when duplicating in the way you mentioned above?


    Many thanks.

  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)

    Mirrored Screens on the SAME card are really fast.


    Screens wider than 1920 bits horizontal (and that HP at 2560 wide is a lot wider) require Dual-Link DVI everything, including (Mini) DisplayPort --> Dual-Link DVI ACTIVE adapter, about US$100. If it would work without this expensive thing, nobody would use it!




    The main impact of Flashed cards is that the boot-up screens don't work. But sometimes certain (unexpected) ports don't work either.

  • OxygenStudio Level 1 Level 1 (0 points)

    Ok, that must be the problem then, the flashed card...


    Because when I connect both Dual link DVI ports to the 27" HP screens, then add the HDMI to another screen, I only get 2 displays working at the same time, never 3, even at lower (compatible) resolutions.


    When I unplug 1 of the HP's it then detects the monitor on the HDMI port and vice versa.


    Do you think using the following arrangement would make any difference?


    - Displayport -> Active Displayport / Dual link DVI Adapter to HP monitor 1

    - DVI port1 -> second HP monitor

    - DVI port 2 -> Normal lower res screen


    And then runninf HP monitor 2 and the lower res screen both at 1080?

  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)

    (Mini) DisplayPort conversion to DVI (or HDMI) may require an ACTIVE adapter. Converting it to Dual-Link DVI (or HDMI) requres a very expensive Dual-Link DVI ACTIVE adapter.


    If you have two direct Dual-Link DVI ports I would cable them directly to your hi-res displays.


    Then I would get an ACTIVE Single-Link adapter to DVI, and if needed, a DVI --> HDMI cable


  • OxygenStudio Level 1 Level 1 (0 points)

    Ok, but if I use both the DVI's for the hi-res displays then that leaves only the HDMI or Displayport to attach to the 1080HD screen to, but as I mentioned, when I have all 3 displays connected, only 2 work. DVI + HDMI or just 2 DVI. I never got all 3 working, hence my wondering if it's due to it being a Flashed card, not official Apple.


    Do you think it would work if I connected 1 DVI to hi-res display, 1 Displayport to hi-res display and the 2nd DVI to the 1080 Display?


    I read that Displayport cables need to be version 1,2 compatible in order to carry 2560 x 1440 resolutions, perhaps the Displayport cable that came with the displays is a version below 1.2? and that's why it never worked?


    Here is a pic of the back of the card for clarity:



  • OxygenStudio Level 1 Level 1 (0 points)

    Just a quick update:


    I ordered this:


    http://www.sapphiretech.com/presentation/product/product_index.aspx?leg=&psn=000 1&pid=357&lid=1


    It says it's ATI compatible, and I also found a post here, where someone successfully used one with their mac (running boot camp at least).


    It's defintely a chaper option than trying to convert the Displayport into DVI for the hi-res monitors.


    I'll post here how it goes.


    Fingers crossed.

  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)

    I never got all 3 working, hence my wondering if it's due to it being a Flashed card, not official Apple.


    according to AMD/ATI:


    Connecting multiple monitors for AMD Eyefinity technology couldn’t be simpler. There are four easy rules to remember:

    1. The first two monitors can connect to the graphics card with any display output on your product: HDMI, VGA, DVI or DisplayPort.
    2. The third (or greater) display must be connected to the graphics card via DisplayPort.
    3. If your monitor does not have a DisplayPort connection, you will need an inexpensive active DisplayPort adapter for it. DVI to DP adapters can be had for less than $30 USD.2
    4. Every family of GPUs supports a different maximum number of displays.
  • OxygenStudio Level 1 Level 1 (0 points)

    Ok, that explains that then


    I really hope the Active DP to DVI adapter fixes it. I've sent so many cables etc. back already.


    Thanks again for your help, I'll post the results once I receive the adapter in a few days.



  • OxygenStudio Level 1 Level 1 (0 points)

    ok, so a quick update:


    I got hold of the Saffire DP to Single Link DVI adapter and it doesn't work either


    The screen is detected by OSX, but only a blank screen shows up and the monitor goes into sleep mode. I tried this with several different DVI, single and dual link cables and HDMI... nothing...


    Any suggestions?


    The strange thing is, someone else in another forums said they had success with this adapter... I'm beginning to think it's really because it's a Firmware flahsed card..

  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)
    Adapts:  DisplayPort™   To:  DVI-D Single Link (Active Adapter)
    ManufacturerPart NumberFirmwareMax. ResolutionPurchase
    AccellB087B-005B0.951920x1200Buy Now
    AstronT2M3F01071-H0.951920x1200Buy Now
    BizlinkKS 10039-A310.951920x1200
    StartechDP2DVIS0.951920x1200Buy Now

    Buy Now



  • Grant Bennet-Alder Level 9 Level 9 (53,420 points)

    Maybe the sample you have is bad. Ask saffire support about it.