Microsoft Corp. has released yet another
patch that should improve performance of three-dimensional games in Windows Vista environment. Nvidia Corp. has already started to
recommend the hotfix to its customers along with a new beta driver package. However, it is unclear whether low performance and abnormal behavior is limited to Nvidia’s hardware and software only and does not affect ATI Radeon graphics products.
Microsoft explained that existing games and other graphics applications frequently allocate virtual memory for a copy of the video memory resources that the application uses. However, this is no longer necessary with Windows Vista, which has a special Windows Display Driver Model (WDDM) manager that ensures that the content of every video memory allocation is maintained across display transitions. Still, the new operating system (OS) has a mechanism to emulate the behavior of previous versions of the OS for compatibility issues.
However, if an application creates its own in-memory copy of its video resources, or the application uses DirectX 9 or an earlier version, the virtual address space contains the WDDM video memory manager’s virtualized range and the application’s copy. Applications that use graphics APIs that are earlier than DirectX 10 and that target GPUs that have large amounts of video memory can easily exhaust their virtual address space causing low performance or erratic behaviour.
Microsoft said that to address this problem, the world’s largest maker of software is changing the way that the video memory manager maintains the content of video memory resources. This change
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