ATI 4870 strange pcie config.

Discussion in 'Mac Pro' started by sutt359, Feb 13, 2012.

  1. sutt359, Feb 13, 2012
    Last edited: Feb 13, 2012

    sutt359 macrumors newbie

    Feb 12, 2012
    Hi Guys
    Ive just managed to get a PC ATI 4870 working my Mac pro 1.1 and with the Apple bootscreen but something strange is happening. I found some instructions on on how to create a mac rom from the pc rom by adding the efi part to it.

    Now heres the odd bit.

    It will only boot in slot 2 with with the pcie system config set at x1 if you change it to x8 it refuses to be seen. If you stick it in slot 1 as it runs at x16 it cant be seen.

    I know slots 1 and 2 work as i still have the old nv7300 and been testing.

    Ive also tested other 4870 roms, again it wont work in slot 1 at all and x1 in slot 2

    Any thoughts?
  2. rtarnoldiii macrumors newbie

    Dec 23, 2012
    Same problem

    Did you ever figure out a solution to this? I'm having the same issue
  3. PowerPCMacMan macrumors 6502a


    Jul 17, 2012
    PowerPC land
    Possible solution


    It sounds like the slots are mixed up. Go to your system folder on the root of your drive. Look for "CoreServices(folder with an X). Find Expansion Slot Utility and run it.

    Its possible the slot configuration might be off. This utility(only works on 1,1 Mac Pro) might resolve the problem.
  4. gpzjock macrumors 6502a

    May 4, 2009
    It may matter which version of OS X you are using, not sure.
  5. 666sheep macrumors 68040


    Dec 7, 2009
    Try to reset PRAM. I've had similar issue: my card was able to run only x8 and Slot Utility was saying that's maximum speed. PRAM reset fixed this.

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