To support multiple graphics adapters in Windows Vista, the following conditions must be true:
· All the graphics adapters must use the same driver model. Therefore, all the graphics adapters must use Windows XP Display Driver Model (XDDM) drivers. Or, all the graphics adapters must use Longhorn Display Driver Model (LDDM) drivers.
· If the graphics adapters use Windows Vista Display Driver Model (WDDM) drivers, all the graphics adapters must use the same driver. For example, you may have two graphics adapters that use the same driver. Or, you may have a Dualview graphics adapter.
To work around this issue, use a multiple graphics adapter configuration that supports WDDM drivers. To support multiple graphics adapters in Windows Vista together with WDDM drivers, use one of the following configurations:
· Use a Dualview graphics adapter.
· Use a dual-lane PCI Express computer system that has two homogeneous graphics adapters.
This issue may occur because the Windows Vista Setup program detects and configures only one graphics adapter. You expect all the installed graphics adapters to be configured in Windows Vista.
- Refer to Microsoft knowledge base,
Article ID: 929456- Multiple monitors are not enabled on a computer that you upgrade from Windows XP to Windows Vista