Best Second Video Card for 4870

Discussion in 'Mac Pro' started by Fomaphone, Aug 6, 2009.

  1. Fomaphone macrumors regular

    Jan 11, 2009
    I'm running two 20 inch monitors with my 4870... I want to purchase another video card for driving another monitor--a 1080p hdtv that i'll be using as a preview monitor in FCP and after effects as well as in 3d modeling programs. i'd like to maximize my machine's potential in SL.

    i can wait a month or two to do this, because i'm planning to replace my RAM with three 4gb sticks to start.

    i'd like to get the most powerful card I can. Would getting a Blackmagic IO card contribute in any way?
  2. Chad H macrumors 6502a

    Chad H

    Feb 13, 2008
    Auburn, AL
    I wonder how the Nvidia GT120 would fair in that department?
  3. nanofrog macrumors G4

    May 6, 2008
    You could use another 4870, and just get a pair (2x) of PCIe 6pin Y power cables to attach to the power cables used on the logic board (ATI x1900 power cables).
  4. wpc33 macrumors 6502


    Jul 2, 2006
    Vancouver, BC
    Please correct me if I'm wrong here, but doesn't the primary card do all of the OpenGL work by itself? Macs don't do crossfire, and I believe you can use the cheapest secondary card you can find, so long as it will drive your resolution.
    Am I crazy?
  5. seisend macrumors 6502a


    Feb 20, 2009
    Switzerland, ZG
    The GT 120 is cheap and a nice card too. You can watch Full HD Videos without any problems and it's very smooth.
  6. dekka007 macrumors member

    Jun 6, 2009
    How does it know which card to use. Say for example you have a 4870 and a GT120 driving your second monitor.

    You load up say a game. How does the OS know which card you wish to do all the graphics intensive work. ie you would want the 4870 doing it and the GT120 not doing much at all really.
  7. nanofrog macrumors G4

    May 6, 2008
    The card that the monitor is attached to is responsible for it's own OpenGL computations (i.e. works with multiple card vendors simultaneously), so no ability to use one card for the calculations and transfer completed data to other cards via the PCIe bus (load sharing, but is done over a different interface, i.e. Crossfire/SLI). As you mentioned, it's not supported under OS X.

    Either card would work, but given the usage ("a preview monitor in FCP and after effects as well as in 3d modeling programs"), I'd think it needs to be a fast card to keep the frame rates high.
  8. PurpleLogix macrumors member


    Jul 2, 2009
    Sydney, Australia
    Keep in mind that FCP doesn't like having a second card installed. It gets a little confused.

    Trust me it happened to me and drove me nuts.

    You can have 2 cards inside. but if you want to use FCP, DVDSP they don't work and cause problems.

    Get the black magic for the previewing
  9. Genghis Khan macrumors 65816

    Genghis Khan

    Jun 3, 2007
    Melbourne, Australia
    nah, seriously...GT120 is probably your best bet (power cable issues otherwise)

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