We invested a lot of time into making parallel programming “just faster” for .NET 4.5.  You’ve already seen some neat tricks to ConcurrentDictionary.  There’s a lot more to say about improving the performance of the Task Parallel Library, and Joe Hoag has a written an excellent paper on the subject:

TPL Performance Improvements in .NET 4.5

The paper examines some of the changes made to TPL in .NET 4.5, compares times for selected operations in .NET 4 vs .NET 4.5, and makes some general “best practices” recommendations for those interested in using TPL performantly in .NET 4.5.

Enjoy!