Are there any performance considerations from referencing a 5MB .Net assembly?

Today a co-worker mentioned he had issues with a large "enterprisey frameworky" project that when compiled was 5mb in size. The concern was that to use a even a small piece of functionality of the assembly you had to referen开发者_Python百科ce the entire thing and that is bad for some reason.

I'm wondering if there are any performance or other disadvantages from loading such a big assembly in a website deployment hosted on IIS?

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The first time a type is used, the assembly will be loaded. Loading 5MB from disk does have a performance cost (although this is not huge). Also, the assembly will stay in memory for the life of the AppDomain, so there's a bit of memory cost (again, not huge).

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Don't optimise using anecdotal evidence. Get some hard numbers and then determine whether the problem exists for you.

Generally I'd say that its not a problem for me anywhere - but I don't download these assemblies on demand via HTTP over unreliable links, on a server with low memory - your use case may be different.

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The major disadvantage is resource consumption; that .DLL stays in memory as long as the program is executing. 5MB isn't actually all that bad, though... System.dll alone, for example, is 3MB.