The Mobile Intel® 915GM/GMS, 910GML Express Chipset Family has dedicated multimedia engines (Intel® Graphics Media Accelerator (GMA) 900) that execute in parallel to deliver high performance 3D, 2D, and video capabilities. These two engines are seen in the Device Manager as two instances of Mobile Intel® 915GM/GMS, 910GML Express Chipset family (see Figure 1). If you double-click each adapter name, you see the first one is identified as "PCI bus 0, device 2, function 0" and the second one identified as "PCI bus 0, device 2, function 1."
The existence of multiple display devices on a single system allows for a number of possible configuration options. For example, two devices can be driven independently with different content, resolutions, and color depth to increase desktop space. Another possible configuration sends the same content to different monitors to give a presentation to a large audience. For more information on these multidisplay configuration options, see: Multimonitor: Understanding multidisplay options.