There are two ways of connecting the monitors to your two NVIDIA Based QuadroFX graphics cards.
Option #1- Connect both monitors to a single Quadro graphics card
Option #2- Individually connect the monitors to two Quadro graphics card
Option 1 offers more flexibility in terms of allowing you to configure a variety of Multi-Display Modes (Dualview, Horizontal Span, Vertical Span, Clone).
Option 2 will only support Dualview mode. Unlike Horizontal Span or Vertical Span mode, Dualview treats each display as a separate device. This means that the Windows taskbar will not be stretched across displays and 3D applications are not accelerated as efficiently when the application spans displays. So if you need to span your application across two monitors, it's better to go with Option 1 and use one of the Span modes.
Note: Article is not applicable for Quadro NVS-Based video cards. Additionally, Horizontal and Vertical Span modes are not supported in Windows Vista and newer operating system.