Does Comvisible-enabled attribute slow down .NET App?

Question

Please help me to answer whether Comvisible-enabled attribute slows down .NET App?

Answer 1

No- ComVisibleAttribute is just an inert attribute until someone looks for it and then performs relevant acts in a context based on the metadata information stored in the custom attribute's serialized form.

Normal execution of a class is not impacted by the presence or absence of the attribute.

An example of something that looks for it is the regasm.exe tool - the more items you have marked ComVisible, the more will need to be registered / get registered / will get into the pool of registered stuff (in the Windows Registry in this instance) weighing down your system overall.