Using the following simple file:

```
using System;

public class Program{
        [STAThread]
        public static void Main(string[] args){
            Console.WriteLine("Boo");
        }
}

```

And then using the following command:

```
csc /target:exe /debug:pdbonly HelloWorld.cs

```

If you run this command and the PDB does not already exist then the PDB file size is 12KB. Otherwise, if the PDB file exists, then the new file size is 14KB.

```
Microsoft (R) Visual C# Compiler version 4.0.30319.17929
.NET 4.5

```

Anyone have any ideas what would explain this?

**UPDATE:**

1. I do not experience this with .NET 3.5 and from the comments .NET 4 either.
2. Using pdb2xml (<http://blogs.msdn.com/b/jmstall/archive/2005/08/25/sample-pdb2xml.aspx>), I cannot see any difference between the small and the larger one.