.NET 4.0 vs 3.5 runtime performance

Now that VS2010 is in RC it seems it's only matter of weeks until first new 'core' runtime release since 2.0. Whilst I do not have immediate needs to upgrade I'm wondering if anyone has done some performance testing/benchmarking between the two.

If there are any noticeable performance gains then it would be beneficial to recompile开发者_C百科 existing, working, applications.

TIA, Dejan

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ASP.NET 4 Runtime 
      o Focused on two areas
            + Performance
            + Extensibility
      o New resource monitoring options
      o New performance features
            + Session state
            + Improving perceived application startup
      o Output cache extensibility

Check this link http://ecn.channel9.msdn.com/o9/pdc09/ppt/FT57.pptx

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I have found .NET 4.0 to be just a tiny bit slower in one test suite we run. The test runs a bunch of queries against a SQLite database using System.Data.Sqlite, and they run 1-2% faster on .NET 3.5 compared to 4.0. Not sure why they are faster, but we are talking about milliseconds here so I'm not too worried.

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Don't get your hopes up, .NET 4.0 is definitely not a perf oriented release. Before anything else, it is a compatibility release. Five long years of MSFT not being able to release a side-by-side installable version of the CLR and the base class libraries come to end.

Better yet, it is a SxS version that even supports running old versions of the CLR together with the new version in one process. That's an awesome accomplishment, I didn't think it was possible. The many BCL additions are cream on the cake.

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Its too early to have an answer to this question has we just now have the RC release.

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Depends.
I utilize LINQ very much, and there is a significant performance improvement.
Given by the profiler of VS2010 the difference is up to 230% faster.
But this is of course only a specific part of .NET 4.0.