How doest MP determine primary video card

[wa5655]

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. I had 2xQuadro 4000 before and they boot just as it should, slot 1 first.

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

TIA for any hints on how to solve this.

 

[ActionableMango]

I believe Switchresx software will do this.

Alternatively, a single 5770 could certainly handle two monitors by itself.

 

[goMac]

Have you tried swapping positions of the cards?

(or better yet, just swapping the cables?)