Comment by rdw

You're right, and it's got more layers than that. C# does have value types, which are not boxed, and using them judiciously can avoid garbage. However, they are a more recent addition to the language (which started as a lame Java clone), and so the standard library tends to not know about them. Really trivial operations will allocate hundreds of bytes of garbage for no good reason. Example: iterating over a Dictionary. Or, IIRC, getting the current time. They've been cleaning up these functions to not create garbage over tiem, of course, but it's never fast enough for my taste and leads to some truly awful workarounds.