gistfile1.cs

using System;
using System.Diagnostics;

namespace QuickCS
{
    interface ITarget
    {
        void DoNothing(int i);
    }

    class Target : ITarget
    {
        public Target(Tester eventRaiser)
        {
            eventRaiser.AnEvent += DoNothing;
        }

        private int _i;
        public void DoNothing(int i)
        {
            _i = i;
        }
    }

    class Tester
    {
        private const int IterationCount = 10000000;

        public event Action<int> AnEvent;

        public void Go()
        {
            var t = new Target(this);

            var sw = new Stopwatch();
            sw.Reset();
            sw.Start();
            for (var i = 0; i < IterationCount; i++)
            {
                t.DoNothing(i);
            }
            sw.Stop();
            Console.WriteLine("{1} direct reference calls     : \t{0} s", sw.ElapsedMilliseconds / 1000.0, IterationCount);

            ITarget ifTarget = t;
            sw.Reset();
            sw.Start();
            for (var i = 0; i < IterationCount; i++)
            {
                ifTarget.DoNothing(i);
            }
            sw.Stop();
            Console.WriteLine("{1} calls through an interface : \t{0} s", sw.ElapsedMilliseconds / 1000.0, IterationCount);

            sw.Reset();
            sw.Start();
            for (var i = 0; i < IterationCount; i++)
            {
                AnEvent(i);
            }
            sw.Stop();
            Console.WriteLine("{1} invocations of an event    : \t{0} s", sw.ElapsedMilliseconds / 1000.0, IterationCount);

            var anAction = new Action<int>(t.DoNothing);
            sw.Reset();
            sw.Start();
            for (var i = 0; i < IterationCount; i++)
            {
                anAction(i);
            }
            sw.Stop();
            Console.WriteLine("{1} calls through Action<int>  : \t{0} s", sw.ElapsedMilliseconds / 1000.0, IterationCount);
            Console.ReadLine();
        }
    }

    class Program
    {
        public static void Main()
        {
            new Tester().Go();
        }
    }
}