An extension should make no difference, it's the contents that make a difference. A .ini has more information than a .mrc. A .txt and a .mrc have exactly the same information, there should not be any speed difference. In my reply I was simply commenting on the ini slower than mrc portion of his post, I didn't even notice the comment about .txt vs .mrc, I guess mainly because I didn't expect anyone to say something like that...
