Viewport Renderer
The technology used for the Viewport display (GPU framework and graphics card) can also be used for rendering in the Picture Viewer. This happens if you define Viewport Renderer as the renderer in the Render Settings menu. This will render quite quickly but at a lower quality than with the other renderers. This is, however, a high enough quality for numerous purposes (see also GPU-Framework).
You can use the Viewport Renderer to render images and animations at reduced quality for preview purposes.
What can be rendered and at which level of quality can be defined in the Basic and Filter menus.