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3 monitors problem

By beri10 ยท 10 replies
Aug 10, 2014
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  1. Hi,

    I'm trying to connect 3 monitors to my Sapphire HD 7770 OC edition which has 2 mini DP ports,1 HDMI and 1 DVI port. So I have 2 adapters mini DP to DVI (the 10$ ones from amazon) and I have a Sapphire HDMI to DVI adapter(maybe I could use that in some combination). So I connect 2 monitors via DVI cables into the DP adapters, and one monitor into the DVI output of the card via VGA cable with a VGA/DVI adapter. And I cannot duplicate the 3rd monitor in catalyst. So it recognize 3 monitors but I cannot duplicate the 3rd, only 2 monitors are working in the same time and I can chose which ones...So should I get a new monitor with a DVI output, or buy new active adapters becouse I think the ones I have aren't active. In this case can I buy just one or do I have to buy 2 ? Or can I buy 1 active DP and then use the HDMI to DVI adapter ? I hope someone can help me.

  2. St1ckM4n

    St1ckM4n TS Evangelist Posts: 2,887   +626

    That card should support up to 4 displays, so perhaps the non-active adaptors are the problem.

    Maybe someone else with more experience here can confirm.
  3. ETF Soldier

    ETF Soldier TS Evangelist Posts: 469   +138

    This isn't an issue with the card I don't think, I think it's an issue with Windows or something, I remember a friend saying if you want 3 or more, you need a little box or something, or some special software.
  4. St1ckM4n

    St1ckM4n TS Evangelist Posts: 2,887   +626

    Windows 7 does 3-screens fine if the GPU supports it. By not using active adaptors you're forcing the GPU to output the analogue signal, which then causes it to not be able to output 3+ digital signals.
    jobeard likes this.
  5. ETF Soldier

    ETF Soldier TS Evangelist Posts: 469   +138

    Oh right, fair enough! With my PC I have 2 monitors (1680*1050 and 1240*1024)) which both use DVI, and then I have a HDMI to connect it to my TV, and for some reason it only lets me do 2 at a time.
  6. St1ckM4n

    St1ckM4n TS Evangelist Posts: 2,887   +626

    That might depend on your GPU. GPU's have a limit on the screens it can output separately, whereas Windows is very high (10+, for sure).
  7. AlbertLionheart

    AlbertLionheart TechSpot Chancellor Posts: 1,997

    Due to eyesight problems I have been running 4 monitors for about 6 years and on a variety of graphics cards using either DVi or VGA outputs. In each case I have been limited to two monitors on each graphics card and I have always understood this to be a limitation of Windows. Windows will allegedly support 9 monitors - the most I have ever run was 5 monitors and this needed a third graphics card to make it work.
  8. Spykezxp

    Spykezxp TS Addict Posts: 296   +73

    Its not Windows, its most likely you have a Passive adapter (not an Active one). I made the same mistake the first time I tried to hook up 3 monitors to my Sapphire 7870. You have to make sure that it is Active. The following is exactly how I have mine hooked up: HDMI cable from card to 37" 1080p LCD TV, Active Display Port adapter (to DVI) which goes to a 22" LED monitor, and finally just a DVI cable from card to 21.5" LCD Monitor. This allows all three to run at the same time.
    • The first two monitors can connect to the graphics card with any display output on your product: HDMI, VGA, DVI or DisplayPort.
    • The third (or greater) display must be connected to the graphics card via DisplayPort.
    • If your monitor does not have a DisplayPort connection, you will need an active DisplayPort adapter for it.
  9. nickc

    nickc TechSpot Paladin Posts: 921   +11

    Spykezxp, may I ask how one activates Display Port? and I know that probably sounds dumb, but I am 60+ years old and when I started computers they were done in a building that was the size of a basketball court today.

    thank u

    I like u're quote below or the signature :)
  10. Spykezxp

    Spykezxp TS Addict Posts: 296   +73

    You can't "activate" the Display Port.
    Passive adapters are merely a cable to go from Display Port to DVI/HDMI/VGA. The video card detects the monitor as such, and outputs the required signal (DVI/HDMI/VGA).
    Active adapters, on the other hand receive a Display Port signal from the video card, and convert it to DVI/HDMI/VGA. They will always have some sort of onboard DAC or video converter chip which they use to convert the Display Port signal.
    Usually the less expensive ones you can buy are the Passive adapters (usually around $10 or less). Active adapters you will need to spend more money to purchase (usually around $25+).
  11. Josh Peters

    Josh Peters TS Rookie

    THANK YOU!!! I have searched the www forever and ur the only one who presented the real answer. thank you thank you thank you!

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