fasterCopy.cs

  /// <summary> Fast file move with big buffers
  /// </summary>
  /// <param name="source">Source file path</param> 
  /// <param name="destination">Destination file path</param> 
  static void FMove (string source, string destination)
  {
   int array_length = (int) Math.Pow (2, 20);
   byte[] dataArray = new byte[array_length];

   FileStream fsread = new FileStream (source, FileMode.Open, FileAccess.Read, FileShare.None, array_length * 2);
   BinaryReader bwread = new BinaryReader (fsread);
   FileStream fswrite = new FileStream (destination, FileMode.Create, FileAccess.Write, FileShare.None, array_length * 2);
   BinaryWriter bwwrite = new BinaryWriter (fswrite);

   for (; ; )
   {
    int read = bwread.Read (dataArray, 0, array_length);
    if (0 == read)
     break;
    bwwrite.Write (dataArray, 0, read);
   }
   bwwrite.Close ();
   fswrite.Close ();
   bwread.Close ();
   fsread.Close ();
   File.Delete (source);
  }

fileShare.ReadWrite.cs

  using(var inputFile = new FileStream(
         "oldFile.txt", 
         FileMode.Open, 
         FileAccess.Read, 
         FileShare.ReadWrite))
     {
        using (var outputFile = new FileStream("newFile.txt", FileMode.Create))
        { 
            var buffer = new byte[0x10000];
            int bytes;

            while ((bytes = inputFile.Read(buffer, 0, buffer.Length)) > 0) 
            {
                outputFile.Write(buffer, 0, bytes);
            }
        }
    }