The Desktop Window Manager is a compositing window manager. This means that each program has a buffer that it writes data to; DWM then composites each program’s buffer into a final image. By comparison, the stacking window manager in Windows XP and earlier (and also Windows Vista and Windows 7 with Windows Aero disabled) comprises a single display buffer to which all programs write.
ALt+Tab with Windows Vista will show the 3D flip view shown. Later versions of Windows changed this to support virtual desktops which are now available with Window 10 which can show 6 or more active desktops in parallel.
tt was originally created to enable portions of the new “Windows Aero” user experience, which allowed for effects such as transparency, 3D window switching and more. It is also included with Windows Server 2008, but requires the “Desktop Experience” feature and compatible graphics drivers to be installed.
- A GPU that supports the Windows Display Driver Model
- Direct3D 9 support
- Pixel Shader 2.0 support
- Support for 32 bits per pixel
- Passes the Windows Aero acceptance test in the Windows Driver Kit (WDK)
In Windows 7, the Desktop Window Manager has been reworked to use Direct3D 10.1, but the hardware requirements remain the same as in Windows Vista; Direct3D 9 hardware is supported with the “10 Level 9” layer introduced in the Direct3D 11 runtime. Windows 8 has the same requirements as 7, but it can also use software rendering when compatible video hardware is absent.