Is referencing a method/variable in an external namespace more memory efficient than including it entirely?

Question

So is the following equivalent in memory usage?

System.Threading.Thread.Sleep(500);

vs

using System.Threading;
...
Thread.Sleep(500);

I would have thought that the less namespaces you're 'using' in memory the better, but I've heard that the former example has to load the namespace into memory regardless. I know Sleep isn't the best example of a memory hungry method but it's just an example.

Answer 1

The using statement doesn't cause anything at all to be loaded, it only tells the compiler where to look for classes.

The two examples produces exactly the same code.