I ask since a project I work on generates a single, monolithic DLL of about 50 MB size.
Does a large library like this one impede performance, or can it bring other gotchas?
UPDATE:
I work with Embercadero RAD Studio Delphi 2010 on Windows (XP|Vista|7).
In .NET, you should prefer a few large assemblies rather than many small assemblies.
See: Does .NET assembly size affect performance?