If you want to set a rectangle section of the screen to draw to, set the GrpahicsDevice.ScissorRectangle to a rectange and set the ScissorTestEnable property of the GraphicsDevice.RasterizerState to true.
GraphicsAdapter is used to deal with all the graphic output devices a pc might have (XBox and WP7 only have one), and their characteristics.
GraphicsDevice has a back buffer and uses double buffering. the Present method does the flip, and there are several flip modes
- .PresentInterval.One (Flips when the display is in vertical retrace phase)
- PresentInterval.Two (Flips every other vertical retrace)
- PresentInterval.Immediate (Flips as soon as possible, can cause tearing but good for measuring performance)
GraphicsDevice.SupportedOrientations lets you determine the positions you let the game work in WP7.