The compiled program runs MUCH more slowly after I switched to VS 2010

Question

One of our important enterprise applications (C #) reduces hi-rez images, and we put a lot of effort into optimizing it. It performs over 2.5 million operations in 2.5 seconds.

We used VS 2005 for years, and last week we moved everything to VS 2010.

Same exact project code.

Now, when I create the application and launch it (outside the VS 2010 IDE), this same operation takes 5 + seconds each time.

This is a big problem, and it hurts. I currently have Release mode set (same as in VS 2005).

Any idea what could lead to double the execution time when the code is exactly the same?

Answer 1

You are probably seeing a change because you switched from targeting the .NET 2.0 runtime to the .NET 4.0 runtime.

You mentioned that you have very optimized the code for performance. I assume that some of the optimizations actually infringe on your performance, rather than helping it now (because the internal implementation details of the Framework that you relied on for optimization have changed).

My suggestion was to run your code through Profiler (e.g. Redgate ANTS Performance Profiler or JetBrain DotTrace ) and see where the new bottlenecks are. You can move from there.