Microsoft received a patent that explains a "compositing desktop window manager".
The patent was confirmed on November 15 and was filed about a year ago as an update to a 2007 patent. According to Microsoft, the compositing desktop window manager (short CDWM) would draw "the window to a buffer memory for future reference, and takes advantage of advanced graphics hardware and visual effects to render windows based on content on which they are drawn." The initial idea for such an approach dates back to a 2003 patent application and includes ideas for Windows Vista and its DWM / Aero Glass interface, which required, in comparison to Windows XP, a substantial bump in GPU horsepower.
However, using a GPU for general purpose applications is much more popular and realistic today as many more powerful graphics chips are deployed in mainstream computing systems than was the case when Vista was launched. According to the patent, application software directly accesses the CDWM via an API, which connects the application to a subsystem programming interface as well as an interface object manager and theme manager. A legacy subsystem is still present as a fallback option. A unified compositing engine (UCE) that acts as a link to a 3D graphics interface, such as OpenGL or Direct3D, is part of the invention.
The timing of the patent application suggests that the technology is not tied to the development of Windows 8 and the update could simply address inaccuracies. One indication for this thought is also a patent drawing that shows windows that combine different geometric shapes such as rectangles and ovals - which is not something that is pursued by Microsoft today. However, much more advanced GPU acceleration could help Microsoft tremendously with the deployment of Windows 8 on entry-level computers, including ARM systems.