Visual F# 2010 for Technical Computing includes a variety of changes throughout the book, some affecting changes to the language and others affecting the use of libraries. The three most prominent changes are:
Chapter 10: Concurrent Programming now covers the final production-quality implementation of asynchronous workflows in the F# 2.0 language.
Chapter 11: Parallel Programming now replaces the TPL CTP with the constructs for shared-memory parallelism that have been integrated into .NET 4. Both the API and the performance characteristics have changed considerably.
Chapter 12: Performance has been completely revamped due to massive improvements in the F# compiler and the new garbage collector in .NET 4.
One particular surprise was the substantial difference in performance characteristics between Visual Studio 2010 and the F# prereleases. Several of the benchmarks covered in the book show 400% changes!