I've migrated a large ASP.NET solution from Visual Studio 2008 (.NET 3.5) to Visual Studio 2010 (.NET 4.0).
I also installed the new version of the Web Deployment Project for VS 2010, because the solution also includes a web deployment project which I'm using to precompile .aspx/.ascx etc. into a single DLL.
I've noticed that the new version of the web deployment project takes way more time to compile and merge the assemblies - instead of 5 minutes in VS2008 it takes 15 or 20 minutes now in Visual Studio 2010.
Does anybody know what could be the reason for such a performance loss?
UDPATE
I ran Process Manager during the compilation. It showed me that aspnet_merge is spending a lot of time on accessing (file IO) assemblies which in my opinion should not be part of the merge process.
For example, even .NET Compact Framework assemblies which I am sure I'm not referencing in any way are accessed on file level (at least that's what Sysinternal's Process Manager shows me.)