PLINQ-test.cs

using System;
using System.Diagnostics;
using System.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var source = Enumerable.Range(1, 100000000).ToArray();

            {
                var sw = Stopwatch.StartNew();
                var result = source
                    .Where(n => n % 2 == 0)
                    .Select(n => n * 2)
                    .ToArray();

                sw.Stop();

                Console.WriteLine(sw.ElapsedMilliseconds); // 1204
            }
            {
                var sw = Stopwatch.StartNew();

                var result = source
                    // できたら並列処理してもいいよと伝える
                    .AsParallel()
                    // ここでむりくり並列化
                    .WithExecutionMode(ParallelExecutionMode.ForceParallelism)
                    .Where(n => n % 2 == 0)
                    .Select(n => n * 2)
                    .ToArray();

                sw.Stop();

                Console.WriteLine(sw.ElapsedMilliseconds); // 975
            }
        }
    }
}