Mac pro 2010 x3 crossfire possible?

Discussion in 'Mac Pro' started by redarc, Jan 22, 2012.

  1. redarc macrumors member

    Joined:
    Sep 6, 2011
    #1
    I would ask to some of the guru of this forum.. if the motherboard of mac pro is capable to make 3 way crossfire... or for example.. what if i have 5870 in first x 16 pcie-express and hd 5970 "hd 5870 x2 " in 2nd pcie...still answer i want are

    1) Mac Pro mobo.. is able to do x3 5870 x16 x16 x8 or there is hardware limitation? sure i need psu external.. allready got it and working

    2) if hardware lmitation for 3-way crossfire what about x1 5870 + 5970? thanks for help!
     
  2. goMac macrumors 603

    Joined:
    Apr 15, 2004
    #2
    You can, but just like a PC, the gains may not be worth it. You'll be starved for PCI lanes.

    A single 5970 is probably your best, and easiest, bet. It should be able to achieve similar performance.
     
  3. redarc thread starter macrumors member

    Joined:
    Sep 6, 2011
    #3
    i'm not satisfated from answer.. it isn t complete.. someone else.. that got good experience... can answer please? with more info? thank you
     
  4. velocityg4, Jan 22, 2012
    Last edited: Jan 22, 2012

    velocityg4 macrumors 68040

    velocityg4

    Joined:
    Dec 19, 2004
    Location:
    Georgia
    #4
    The 2010 Mac Pro has 40 PCIe lanes. Two of the slots are full x16 slots the other two only run at x4. So when running three cards they would run at x16 x16 x4.

    In this case the 5970 only takes one PCI-e x16 slot so the 5870 + 5970 would be running x16 and x16. To get crossfire working all you should need is the ATI catalyst software running in Windows and a crossfire bridge connecting the two cards.

    This guy gives the answer for two 5870's in the Mac Pro. In Windows crossfire works in OS X they work independently. Your situation should be similar. In Windows it should work in OS X the will be independent.

    Here is a post from a Netkas.org forum member saying they have a 5970 and 5870 crossfired in Windows in a Mac Pro. Apparently you can also make the 5970 work in OS X by adding it to the ATI kexts.

    http://www.insanelymac.com/forum/index.php?showtopic=230874

    Note: If you go about modding kext files you should make a backup first. You will also have to use terminal to repair the ownership and permissions of the file. As it has to be copied out of the system folder and put back in to be modified.
     

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