Windows 7 supports heterogeneous multi-adapter configurations, whereas Windows Vista did not. In Windows 7, a system can have a heterogeneous multi-adapter configuration, with multiple GPUs that require different WDDM drivers. The WDDM model for Windows Vista required that all display adapters use the same driver. Linked Display Adapters A linked display adapter (LDA) is a mode of operation in which multiple physical adapters appear merged into a single logical adapter. From an application’s point of view, only the single logical adapter is visible. However, the underlying WDDM driver uses all the physical adapters in the link to improve the performance of the logical adapter. The logical adapter typically offers much higher performance than any individual physical adapters can provide. The driver can link physical adapters that have identical capabilities and identical memory configurations. Every physical adapter that is part of a logical adapter must be visible on the PCIe bus as an independent device. WDDM assumes that all nodes in a given physical adapter have uniform access to the physical adapter’s memory. LDAs are supported only on the PCIe bus. LDA configuration is not supported on AGP systems. Feature Support for Multi-GPU Systems Windows 7 supports nearly all WDDM v1.1 graphics features on multi-GPU systems as on single-GPU systems. However, Windows 7 disables the new system memory savings for the Aero Glass theme if two or more active graphics adapters are present. When a system supports multiple monitors by using multiple GPUs that are not linked, Windows disables device bitmaps if the desktop extends across more than one of the monitors. Because system memory savings for Aero Glass depend on the device bitmaps, this feature is not available on such systems.
Windows 7 supports heterogeneous multi-adapter configurations, whereas Windows Vista did not. In Windows 7, a system can have a heterogeneous multi-adapter configuration, with multiple GPUs that require different WDDM drivers. The WDDM model for Windows Vista required that all display adapters use the same driver. Linked Display Adapters A linked display adapter (LDA) is a mode of operation in which multiple physical adapters appear merged into a single logical adapter. From an application’s point of view, only the single logical adapter is visible. However, the underlying WDDM driver uses all the physical adapters in the link to improve the performance of the logical adapter. The logical adapter typically offers much higher performance than any individual physical adapters can provide. The driver can link physical adapters that have identical capabilities and identical memory configurations. Every physical adapter that is part of a logical adapter must be visible on the PCIe bus as an independent device. WDDM assumes that all nodes in a given physical adapter have uniform access to the physical adapter’s memory. LDAs are supported only on the PCIe bus. LDA configuration is not supported on AGP systems. Feature Support for Multi-GPU Systems Windows 7 supports nearly all WDDM v1.1 graphics features on multi-GPU systems as on single-GPU systems. However, Windows 7 disables the new system memory savings for the Aero Glass theme if two or more active graphics adapters are present. When a system supports multiple monitors by using multiple GPUs that are not linked, Windows disables device bitmaps if the desktop extends across more than one of the monitors. Because system memory savings for Aero Glass depend on the device bitmaps, this feature is not available on such systems.
GraphicsGuideWin7.docx