To set up Dual Displays in the Mac OS X (Works the same whether you have two graphic cards or a dual card with two graphic chips and output signals.):
1. Activate the "Multiple Monitor Features" on system level by going to "System Preferences -> Displays" and pressing "Detect Displays".
2. Check the option "Show displays in menu bar".
3. Select the tab "Arrangements" and uncheck the "Mirror Displays" option. It is important to note that while you can Mirror the displays after profiling but they cannot be mirrored while creating profiles for the displays. Now you can calibrate and profile each monitor.
4. Start the ColorMunki software and move the appearing main window on the monitor, which you want to profile. ColorMunki Software will allow you to select Display 1 or Display 2 in the default settings.
5. Perform the profiling process and save the profile. It should automatically be set as default system profile. Feel free to mirror the displays or keep them unmirrored.
To check or assign your current monitor profile:
1. Go to "System Preferences -> Displays -> Color".
2. Open "Displays" (if in the option "Show display in menu bar" was activated). A window with a list of available monitor profiles will appear on each monitor. The active profile will be marked.