Using 2 Video Cards vs. 1 for 3 displays

Discussion in 'Mac Pro' started by Jigga Beef, Oct 5, 2018.

  1. Jigga Beef macrumors regular

    Joined:
    Jan 11, 2009
    Location:
    Philadelphia, Pa
    #1
    I currently have 3 X 28 inch 4K Samsung monitors power off a single AMD Radeon RX 580. All of them using with display port - display port.


    I have 2 X ATI Radeon 5770 1GB VRAM just sitting around collecting dust and 1 spot open in my PCI cards. I would need to use Display port - Mini Display port to connect to the 5770.


    Would I see any benefit or performance increase by installing the 5770 and hooking 1 monitor up to it?
     
  2. tsialex macrumors 601

    tsialex

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    Jun 13, 2016
    Location:
    Brazil
    #2
    How do you gonna feed power to the HD 5770? RX-580 needs the two PCIe AUX power. BTW, HD 5770 only works up to 10.13.6.
     
  3. G5isAlive macrumors 6502a

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    #3
    Technical considerations aside on implementation... (you can get an external power supply)... the question remains, would this help performance? I would love to know that answer.
     
  4. tsialex macrumors 601

    tsialex

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    #4
    I doubt that the HD 5770 will help in any way the RX-580 and even if helps, will warrant to do all the power mods needed to feed a card that stops working at 10.13.6?
     
  5. Jigga Beef thread starter macrumors regular

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    Jan 11, 2009
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    Philadelphia, Pa
    #5
    Well that seems to settle it if its not support its not worth it.

    I thought the Logic board gave me 2 places to get power from and I am only using one with the current card.
     
  6. tsialex, Oct 5, 2018
    Last edited: Oct 5, 2018

    tsialex macrumors 601

    tsialex

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    #6
    If you are using only one with a RX-580, you will damage your logic board.

    75W from the slot plus 75W from the PCIe AUX will get nowhere near the ~230W of maximum power consumption of a RX-580.
     
  7. G5isAlive macrumors 6502a

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    Aug 28, 2003
    #7
    Two separate issues... whether its worth it and whether it would help. I really was only interested in the later.. as I have an open slot in my Mac Pro and have often wondered if two cards were better than one. And actually, for a variety of reasons I don't plan to upgrade that Pro past 10.12. But as indicated, I am not interested in debating is it worth it.
     
  8. tsialex macrumors 601

    tsialex

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    #8
    Two cards are better than one, but not in a disparate situation like HD 5770 and RX-580. Look for tests with dual GTX 1080, people have tested it extensively some time ago.
     
  9. G5isAlive macrumors 6502a

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    Aug 28, 2003
    #9
    Thanks... that makes sense
     
  10. thornslack macrumors 6502

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    Nov 16, 2013
    #10
    I believe the general consensus is running additional monitors on a gpu may increase temperature on the card by a slim margin but has almost no performance impact.
     
  11. devon807 macrumors 6502

    devon807

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    Location:
    Virginia
    #11
    I did this with my 2 RX 580's. Having them attached to different displays actually caused quite a bit of UI lag. The only difference being I was trying to run 2x 30 inch ACD and one 28 Inch 4k Samsung
     

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10 October 5, 2018