Enum OculusSettings.StereoRenderingModeDesktop

public enum StereoRenderingModeDesktop

Name	Description	Value
MultiPass	Unity makes two passes across the scene graph, each one entirely indepedent of the other. Each pass has its own eye matrices and render target. Unity draws everything twice, which includes setting the graphics state for each pass. This is a slow and simple rendering method which doesn't require any special modification to shaders.
SinglePassInstanced	Unity uses a single texture array with two elements. Unity converts each call into an instanced draw call. Shaders need to be aware of this. Unity's shader macros handle the situation.