.Net 3.5 to 4 Migration resulting in Application Slowdown

As I wanted to benefit from new multicore threading improvements from .Net Framework 4, I recompiled all of my solution projects from 3.5 to 4.Everything compiled Ok.

But what was my surprise to see that my application runs much slower when compiled in .Net 4 compared to 3.5. I was not expecting that at all. It is a scientific processing App, so computing time is what it's all about.

I have no clue where to start from, and for the time being, and I prefer to think that I have missed something during the migration process, that is fixable, rather than t开发者_JS百科he App is "per se" running slower in .4 (can't see any logical reason for that...)

Any Ideas are Welcome

here's a small checklist for you:

1. Check, if you are using a Release Build - maybe you've done a Debug Build
2. Check, if all performance optimizations are turned on in the project file.
3. Check your target platform, if it maybe is set to x86.
4. Did you change your code? Compare both versions, if there are significant differences? e.g. are you using Linq?
5. Go and get a Profiler for testing. I would recommend ReSharper dotTrace.

Hope that I could help you

I suggest you use a profiler on both versions and compare the results. It might give you a starting point