.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

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

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.

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.

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

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.