Apple 5870 + PC 5870 for Cross firing?

Discussion in 'Mac Pro' started by revilate, Jun 25, 2012.

  1. revilate macrumors member

    Nov 4, 2011
    Hi all,

    So since we didn't see a viable upgrade at WWDC this year, I'm going to stick with my 2.8 Mac Pro and cross fire a couple of 5870s, and later down the road replace its Xeon with an i7x at some point, all to hopefully tie my computing needs over until the 2013 models come out.

    My question concerning the 5870 cross firing is--while I already have an Apple 5870 installed, could I use a PC version of a 5870 to cross fire them? The difference (of about $200+) is substantial.

    Also, anyone know of some decent non ECC RAM for the i7x switch in the future?

  2. areandres macrumors newbie

    Oct 14, 2011
    I made cross fire with the configuration what you want.
    I buyed a Sapphire 5870 PC Version from ebay.
    Then i buyer some adapter for power. I used DVD SATA bay to take adpt the power to the graficscrad. Then i use the crossfire bridge to connect my Apple 5870 and the Sapphire 5870. After booting to windows over bootcamp it is working like a charm. Just activate crossfire in AMD Panel thats it.

  3. TheDoc macrumors member

    Mar 18, 2008
    As far as I know, you will get zero benefits under OS X. Only Windows will recognize the CF.
  4. ActionableMango macrumors G3


    Sep 21, 2010
    Crossfire does not have reliable driver updates and also has problems both large and subtle in many games. It will not work at all on the OS X side. You will need more power than the MP can safely provide, so you'll have to hack in a secondary power supply or run a mess of an external supply. The 5870 is an expensive card, even on the PC side. It also does not scale very well, so 2x5870 is not twice as fast as a 5870.

    It's basically a bag of hurt. But yes, you can do it if you like.
  5. areandres macrumors newbie

    Oct 14, 2011
    You have a benefit in OSX side. But only when you make 3D Renderings.
    My speed is nearly double as before.
    I use SLG2 this is a GPU based render engine and i must say WOW the seep is amazing.
    My goal was GPGPU Rendering and this solution is quiet good for me and all other who want to render fast.

    Watch the first picture (iPhone) this render was less then 8 Minutes.
    Klick me and tis is quiet fast.

    I am happy with this combination and in bootcamp my games are also much faster then before.
  6. ActionableMango macrumors G3


    Sep 21, 2010
    There is no Crossfire on the OSX side, so you cannot possibly be benefiting from it on OSX. If your rendering is twice as fast, it's simply because your rendering software takes advantage of multiple cards without Crossfire.
  7. areandres macrumors newbie

    Oct 14, 2011
    Correct i never said that i use crossfire on OSX.
    I use only crossfire on Bootcamp thats it. For rendering i don't need crossfire.

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