test.cs

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

namespace loopBenchmark
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch watch = new Stopwatch();
            watch.Start();
            for (int i = 0; i < 10000; i++) ;
            watch.Stop();
            Console.WriteLine("for: " +  watch.Elapsed.ToString());
            int[] intList = new int[10000];
            watch.Start();
            foreach (int i in intList) ;
            watch.Stop();
            Console.WriteLine("foreach: " + watch.Elapsed.ToString());
            Console.ReadKey();
        }
    }
}

output:

for: 00:00:00.0000373
foreach: 00:00:00.0000565