Decorator Pattern Question

Hi

I recently bought the design pattern(C#) package. Having just started to review the code I have a question regarding the 'Decorator pattern'.

What advantage does the '.net optimised code' give over the 'Real World example' given for the decorator pattern?
Is there any documentation regarding the reasoning behind the '.net optimised versions'?

Similarly what would be the advantage of 'optimised code' for the 'chain of responsibility' pattern which has inserted event based handling at the 'top of the chain' compared to the 'real world example'?

Thanks