The GraphicsRenderingMode can be one of:
(0) Dynamic mode is used to provide smooth draws of Graphics. Graphics are redrawn at a high frame rate along with other map features. This requires more work on the part of your machine's graphics rendering pipeline than Static.
(1) Static mode is used to increase draw performance when the GraphicsOverlay may contain many unmoving Graphics. Graphics are rasterized for display. When the map display changes (such as during zoom) the symbols are not redrawn until the map display change is finished. Static rendering mode is not suitable for moving Graphics.