Wondering how to make your Silverlight 3 applications perform better? Is the weight of heavy graphics bringing you down?
Caching visual elements as bitmaps allows you to take advantage of hardware accelaration. Once an object or tree of objects has been cached as a bitmap, it no longer goes through the render phase as the application refreshes, rather, the cached bitmap is rendered.
The cached bitmap swapping is able to take advantage of hardware acceleration from the user’s GPU which can yield significant performance improvements for some scenarios.
Check-out this blog post for more information: http://blogs.msdn.com/silverlight_sdk/archive/2009/07/09/silverlight-cached-composition.aspx
and this Channel 9 video: https://channel9.msdn.com/posts/mtaulty/Silverlight-3-Beta-GPU-Acceleration/