.NET Framework 3.5 Service Pack 1 Beta

 Oh....yes....

Windows Presentation Foundation (WPF) and Visual Designer Changes

• Cold startup performance improvement ranging between 20-45% depending on application size without needing to modify any code.
• Additional WPF features for text, graphics, and media to deliver better performance. For example, effects like DropShadow and Blur were implemented using software rendering; with Service Pack 1 these are now implemented using hardware acceleration. Other examples include:
  • Text, especially when used in Visual and DrawingBrush, is substantially faster.
  • Data scalability improvements - Container Recycling, TreeView virtualization, and more to enable richer data editing support
  • Media performance improvements
  • A much improved WriteableBitmap that enables real-time bitmap updates from a software surface
• Visual Studio 2008 introduced a brand new designer for WPF applications. Since Visual Studio 2008 released many additional features have become available for inclusion in the designers. These include event tab support within the property grid for control events, toolbox support within source mode, and a variety of other common asks and improvements.

http://msdn.microsoft.com/en-us/vstudio/products/cc533447.aspx