Vista Display Driver Model

Once Windows Vista is here, we have a new driver model for display drivers, called the Windows Display Driver Model or WDDM. For users, this should result in better stability and performance, and for driver manufacturers it means a rewrite. But for application-level developers, it is also something to think about.

This is because WDDM is closely related to the new Desktop Window Manager (DWM), that will control drawing to the desktop. Previously, Windows application drew directly to the screen, but in Vista this will change. Of course, your application can still use the "zero handle" to draw to the desktop, but on Vista you will actually draw to an on-memory buffer. Says Technet:

"The DWM is, in essence, a Direct3D application that is active from the moment the computer is turned on. Thus, core features of the WDDM, such as the ability to share the GPU resources and processing, become essential in this scenario."