Microsoft is to overhaul Windows' graphic driver model after realising that the Windows Display Driver Model (WDDM) 1.0 — which will ship with Vista — needs improvement in the way it shares GPU resources between programs and Windows itself.
Steve Pronovost of Microsoft's DirectX team disclosed at WinHEC in Seattle last week that although the WDDM 1.0 introduces some rudimentary task scheduling for GPUs, a new generation of GPU hardware and a major architectural change to the way Windows deals with video cards will be required.
He said that the trouble with WDDM 1.0 is that once one program is using the GPU, other programs are shut out until the process completes. In Vista, that can cause less fluid rendering of on-screen graphics, if multiple programs are trying to use GPU resources at once.
Until now, the inability to share GPU resources hasn't been an obvious problem under Windows XP, because XP uses GDI — a 2D graphics system — to draw windows and operating system interface elements. In general, only 3D games and other major grahics apps use GPU resources, and users only run one such app at a time, he said.
However, inadequate GPU sharing is a problem for Windows Vista, because it uses the GPU to draw all elements of Vista's new Aero interface, and more generally there is a trend towards using the massive computing power in GPUs to process an array of non-graphics tasks as well.
News source: APCStart