启动调试与开始执行（不调试）比较中一个奇怪的现象 ——线程的问题

悬赏园豆：50 [待解决问题]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;
using System.Threading;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

private Thread invokeThread;
        private delegate void invokeDelegate();

private void StartMethod()
        {
}
private void button3_Click_1(object sender, EventArgs e)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            invokeThread = new Thread(new ThreadStart(StartMethod));
invokeThread.Start();
            sw.Stop();
label1.Text = (sw.ElapsedTicks / (decimal)Stopwatch.Frequency).ToString();

        }
    }
}

换用 ThreadPool.QueueUserWorkItem创建的话，执行时间不稳定平均表现依然不及调试状态下的执行速度。