To visualize your scene interactively in the scene view, there are three modes available:
Select this option to draw scene views with low quality settings but reduce draw time. See Renderer > Default Quality Rendering for more information.
Select this option to draw scene views with high quality settings. See Renderer > High Quality Rendering for more information.
Select this option to draw scene views at a high performance. See Renderer > Viewport 2.0 for more information.