Threaded i++ bilion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Threading.Tasks;

namespace simple_performance_test
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch clock = new Stopwatch();
            while (true)
            {
                Console.WriteLine("");
                Console.WriteLine("Starting Test");

                clock.Restart();
                int sum = 0;
                //for (; sum < 1000000000; sum++) ;

                int work = 1000000000 / Environment.ProcessorCount;

                Parallel.For(0, Environment.ProcessorCount, (x) =>
                    {
                        int i = 0;
                        for (; i < work; i++) ;
                        sum += i;
                    }
                );
                clock.Stop();

                Console.WriteLine("Took " + clock.ElapsedMilliseconds + " to iterate to " + sum);
                Console.ReadKey();
            }
        }
    }
}