Do the .Net Chop (Chop a string at a fixed length and insert line feeds)

In coming across this question on StackOverflow I  inspired to write my own version for the question.  I started to think about using a List<string> but decided to create sized array up front.  My version was taking longer than I hoped (mainly because I kept refreshing the site) but I did create a version that used string.Join and Array.Copy.  Wanting to compare the speed differences between a few of the answers I put together this little test of code.

(as a side note I did find a crazy speed difference between string.Join and StringBuilder. )

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;

namespace stringChop
{
    class Program
    {
        //http://stackoverflow.com/questions/1009839/net-split-by-length
        static void Main(string[] args)
        {
            string chopMe = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
            int partLength = 12;

            Stopwatch sw = new Stopwatch();

            //version 1 (my version)
            {
                sw = Stopwatch.StartNew();
                char[] chopMeArray = chopMe.ToCharArray();
                int totalLength = chopMe.Length;
                int partCount = (totalLength / partLength) + ((totalLength % partLength == 0) ? 0 : 1);
                int posIndex = 0;
                char[] part = new char[partLength];
                string[] parts = new string[partCount];
                int get = partLength;
                for (int i = 0; i < partCount; i++)
                {
                    get = Math.Min(partLength, totalLength - posIndex);
                    Array.Copy(chopMeArray, posIndex, part, 0, get);
                    parts[i] = new string(part, 0, get);
                    posIndex += partLength;
                }
                var output = string.Join("\r\n", parts) + "\r\n";
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //203
            }

            //version 2 (based on Aric TenEyck's version)
            {
                var s = chopMe;
                var len = partLength;
                sw = Stopwatch.StartNew();
                List output = new List();
                while (s.Length > len)
                {
                    output.Add(s.Substring(0, len) + "\n");
                    s = s.Remove(0, len);
                }
                output.Add(s + "\n");
                var parts = string.Join("\r", output.ToArray());
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //266
            }

            //version 3 (My version with string builder instead of string.Join inspired by Robert Harvey)
            {
                sw = Stopwatch.StartNew();
                StringBuilder sb = new StringBuilder();
                char[] chopMeArray = chopMe.ToCharArray();
                int totalLength = chopMe.Length;
                int partCount = (totalLength / partLength) + ((totalLength % partLength == 0) ? 0 : 1);
                int posIndex = 0;
                char[] part = new char[partLength];
                string[] parts = new string[partCount];
                int get = partLength;
                for (int i = 0; i < partCount; i++)
                {
                    get = Math.Min(partLength, totalLength - posIndex);
                    Array.Copy(chopMeArray, posIndex, part, 0, get);
                    sb.AppendLine(new string(part, 0, get));
                }
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //98
            }

            //version 4 (based on Joel Coehoorn's code)
            {
                sw = Stopwatch.StartNew();
                List parts = new List();
                var s = chopMe;
                int length = partLength;
                var buf = new char[length];
                using (var rdr = new StringReader(s))
                {
                    int l;
                    l = rdr.ReadBlock(buf, 0, length);
                    while (l > 0)
                    {
                        parts.Add(new string(buf, 0, l));
                        l = rdr.ReadBlock(buf, 0, length);
                    }
                }
                var outparts = string.Join("\r", parts.ToArray());
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //959
            }

            { //version 5 (Fredou's)
                sw = Stopwatch.StartNew();
                string s = chopMe;
                List a = new List();
                for (int i = 0; i <= 7000; i++)
                {
                    s += "a";
                } for (int i = 0; i <= s.Length; i += 76)
                {
                    if ((i + 76) > s.Length) { a.Add(s.Substring(i) + "\r\n"); }
                    else { a.Add(s.Substring(i, 76) + "\r\n"); }
                }
                var outparts = string.Join("\r", a.ToArray());
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //268765 
            }

            { //version 6 (Alan M's)
                sw = Stopwatch.StartNew();
                var outparts = Regex.Replace(chopMe, @"(?<=\G.{76})", "\r\n");
                sw.Stop();
                Console.WriteLine(sw.ElapsedTicks); //10661
            }

            Console.ReadLine();
        }
    }
}