title: What size chunks should I copy files in?
body: <p>Our .NET app copies large files, and needs to give the user feedback; so rather than use <code>File.Copy</code> we read a chunk of one file and write it to the other, and display the progress after each chunk.  Nothing out of the ordinary.  But what's the right size of chunk to use, to give the fastest file copy, assuming the time to display the progress is negligible?</p>