JSI Tip 9578. When you install a new video driver that attempts to map the frame buffer with the write combining attribute enabled, write combining remains disabled until you restart Windows XP or Windows Server 2003?

The subject behavior occurs because the new display driver shares the frame buffer with the VGA (Video Graphics Adapter) display driver. When the VGA driver loads, it maps the frame buffer with the write combining attribute disabled.

Once the frame buffer has been mapped, remapping attempts fails.

To resolve the problem, you must restart your computer. This causes the new display adapter to load before the VGA adapter, allowing it to map the frame buffer with the write combining attribute enabled.