How doest MP determine primary video card

Discussion in 'Mac Pro' started by wa5655, Oct 1, 2011.

  1. wa5655 macrumors member

    Jun 12, 2010
    I have 2x5770 in my '09 MP running SL. one in slot 3 and one in slot 1. One would think MP will pick slot 1 (during start up) to be the primary, however, it picks slot 3. I re-arranged under "Display" and the monitor connects to slot 1 becomes primary (where the menu bar is), but that is only after booting has finished.

    It won't be a problem if both display are in landscape mode, however, the one connects to slot 3 is in portrait mode. :D I had 2xQuadro 4000 before and they boot just as it should, slot 1 first.:confused:

    I tried the PRAM reset and SMC reset, same result.

    TIA for any hints on how to solve this.
  2. ActionableMango macrumors G3


    Sep 21, 2010
    I believe Switchresx software will do this.

    Alternatively, a single 5770 could certainly handle two monitors by itself.
  3. goMac macrumors 603

    Apr 15, 2004
    Have you tried swapping positions of the cards?

    (or better yet, just swapping the cables?)

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