String.Split microbenchmark

Program.cs

using System;
using System.Diagnostics;

public class Program
{
    public static void Main()
    {
        const string test = "This is a sentence to use for testing.";
        string[] separator = new string[] { " " };
    
        var sw = new Stopwatch();
        const int ITERS = 10000000;
        while (true)
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();
        
            Console.Write("A: ");
            sw.Restart();
            for (int i = 0; i < ITERS; i++)
            {
                // Operation A
                test.SplitOld(separator, 1, StringSplitOptions.None);
            }
            var elapsedA = sw.Elapsed;
            Console.WriteLine(elapsedA);
         
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();
         
            Console.Write("B: ");
            sw.Restart();
            for (int i = 0; i < ITERS; i++)
            {
                // Operation B
                test.Split(separator, 1, StringSplitOptions.None);
            }
            var elapsedB = sw.Elapsed;
            Console.WriteLine(elapsedB);
         
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();
         
            Console.WriteLine("A/B     : {0}",
                elapsedA.TotalMilliseconds /
                elapsedB.TotalMilliseconds);
            Console.WriteLine("B/A     : {0}",
                elapsedB.TotalMilliseconds /
                elapsedA.TotalMilliseconds);
            Console.WriteLine("(A-B)/A : {0}",
                Math.Abs((elapsedA.TotalMilliseconds -
                          elapsedB.TotalMilliseconds) /
                         elapsedA.TotalMilliseconds));
            Console.WriteLine("(B-A)/B : {0}",
                Math.Abs((elapsedB.TotalMilliseconds -
                          elapsedA.TotalMilliseconds) /
                         elapsedB.TotalMilliseconds));
            Console.WriteLine();
         
            Console.ReadLine();
        }
    }
}

Results

A: 00:00:01.6835160
B: 00:00:00.1366061
A/B     : 12.3238713351746
B/A     : 0.0811433333570931
(A-B)/A : 0.918856666642907
(B-A)/B : 11.3238713351746


A: 00:00:01.7130745
B: 00:00:00.1377855
A/B     : 12.4329083974729
B/A     : 0.0804317033497376
(A-B)/A : 0.919568296650263
(B-A)/B : 11.4329083974729


A: 00:00:01.6833079
B: 00:00:00.1387093
A/B     : 12.1355085780117
B/A     : 0.0824028093731397
(A-B)/A : 0.91759719062686
(B-A)/B : 11.1355085780117


A: 00:00:01.6823955
B: 00:00:00.1397315
A/B     : 12.0402021018883
B/A     : 0.0830550842533756
(A-B)/A : 0.916944915746624
(B-A)/B : 11.0402021018883


A: 00:00:01.6638048
B: 00:00:00.1403704
A/B     : 11.852960453201
B/A     : 0.0843671084492604
(A-B)/A : 0.91563289155074
(B-A)/B : 10.852960453201


A: 00:00:01.6723702
B: 00:00:00.1425899
A/B     : 11.7285319647465
B/A     : 0.0852621626479592
(A-B)/A : 0.914737837352041
(B-A)/B : 10.7285319647465


A: 00:00:01.6890087
B: 00:00:00.1366335
A/B     : 12.3616001932176
B/A     : 0.0808956756705871
(A-B)/A : 0.919104324329413
(B-A)/B : 11.3616001932176