list2.OrderBy(i => i).ToList();

class Program
    {
        class MyClass : IComparable<MyClass>
        {
            private readonly int _field1;
            private readonly string _field2;

            public MyClass(int v)
            {
                _field1 = v;
                _field2 = "par" + v;
            }

            public int CompareTo(MyClass other)
            {
                return _field1.CompareTo(other._field1);
            }
        }


        private static List<MyClass> CreateList(int size)
        {

            // use the same seed so that every list has the same elements
            var random = new Random(589134554);

            var list = new List<MyClass>(size);
            for (int i = 0; i < size; ++i)
                list.Add(new MyClass(random.Next()));
            return list;
        }

        private static void Benchmark(int size, bool output = true)
        {
            var list1 = CreateList(size);
            var list2 = CreateList(size);

            var stopwatch = Stopwatch.StartNew();
            list1.Sort((a, b) => a.CompareTo(b));
            stopwatch.Stop();
            var elapsedSort = stopwatch.Elapsed.TotalMilliseconds;
            if (output)
                Console.WriteLine("List({0}).Sort(): {1}ms (100%)", size, elapsedSort);

            stopwatch.Restart();
            list2.OrderBy(i => i).ToList();
            stopwatch.Stop();
            var elapsedOrderBy = stopwatch.Elapsed.TotalMilliseconds;
            if (output)
                Console.WriteLine("List({0}).OrderBy(): {1}ms ({2:.00%})", size, elapsedOrderBy, elapsedOrderBy / elapsedSort);

        }

        static void Main(string[] args)
        {
            // ensure linq library is loaded and initialized
            Benchmark(1000, false);

            Benchmark(10);
            Benchmark(100);
            Benchmark(1000);
            Benchmark(10000);
            Benchmark(100000);
            Benchmark(1000000);

            Console.ReadKey();
        }
    }