Parallel programming in .NET - Internals

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

namespace InParallel
{
    class Run
    {

        public static void Main(string[] args)
        {
            Tree myTree = CreateTree(15, 2);
            Console.WriteLine("Press Enter to Run Sequential Sample");
            Console.Read();
            Console.WriteLine("Started");
            Stopwatch watch = Stopwatch.StartNew();
            WalkTree(myTree);
            watch.Stop();
            Console.WriteLine("End");

            Console.WriteLine("Total Time Taken Sequential " + watch.ElapsedMilliseconds.ToString());
            GC.Collect();
            
            //Gives memory out exception
            /*
            Console.WriteLine("Press Enter to Run Threads Sample");
            Console.Read();
            Console.WriteLine("Started");
            watch = Stopwatch.StartNew();
            WalkTreeUsingThreads(myTree);
            watch.Stop();
            Console.WriteLine("End");
            Console.WriteLine("Total Time Taken using Threads " + watch.ElapsedMilliseconds.ToString());
            GC.Collect();
            */
            Console.WriteLine("***************");
            Console.WriteLine("Press Enter to Run Tasks Sample");
            Console.ReadLine();
            Console.WriteLine("Started");
             Console.WriteLine("*** Watch the fun at in Your Task Manager\\Performance Tab. CPU now should be 100%");
            watch = Stopwatch.StartNew();
            WalkTreeUsingTasks(myTree);
            watch.Stop();
            Console.WriteLine("End");
            Console.WriteLine("Total Time Taken using Tasks " + watch.ElapsedMilliseconds.ToString());

            
            Console.ReadLine();

        }
        static Tree CreateTree(int depth, int start)
        {
            Tree root = new Tree();
            root.Data = start;
            if (depth > 0)
            {
                root.Left = CreateTree(depth - 1, start + 1);
                root.Right = CreateTree(depth - 1, start + 1);
            }
            return root;
        }
        static void WalkTree(Tree treeToWalk)
        {
            if (treeToWalk == null) return;
            WalkTree(treeToWalk.Left);
            WalkTree(treeToWalk.Right);

            ProcessItem(treeToWalk.Data);
        }
        static void WalkTreeUsingThreads(Tree treeToWalk)
        {
            if (treeToWalk == null) return;
            Thread leftThread = new Thread(()=>WalkTreeUsingThreads(treeToWalk.Left));
            leftThread.Start();
            Thread rightThread = new Thread(() => WalkTreeUsingThreads(treeToWalk.Right));
            rightThread.Start();

            leftThread.Join();
            rightThread.Join();
            ProcessItem(treeToWalk.Data);
        }
        static void WalkTreeUsingTasks(Tree treeToWalk)
        {
            if (treeToWalk == null) return;
            Task left = new Task(() => WalkTreeUsingTasks(treeToWalk.Left));
            left.Start();
            Task right = new Task(() => WalkTreeUsingTasks(treeToWalk.Right));
            right.Start();

            left.Wait();
            right.Wait();
            ProcessItem(treeToWalk.Data);
        }
        static void ProcessItem(int Data)
        {
            Thread.SpinWait(100000);
        }

    }

    class Tree
    {
        public Tree Left = null;
        public Tree Right = null;
        public int Data=0;
    }

   

    
}