Why Intel 915 graphics don’t have a WDDM driver for Windows Vista

A common question among folks who are upgrading to Windows Vista on slightly older notebooks, tablet PC's, and UMPC's is why the Intel 915 graphics chipset doesn't have WDDM support, as WDDM support is a prerequisite for Desktop Composition. The folks over at the Intel software blog have posted a video with the answer to this question. Follow the link to get the answer straight from the proverbial horse's mouth.