using System;

using System.Diagnostics;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var data = Enumerable.Range(0, 10000).Select((item, index) => index).ToArray();

        var count = 1000000;

        Console.WriteLine(DoTest(count, () =>

        {

            var t = data.FirstOrDefault(item => item == 900);

        }));

        Console.WriteLine(DoTest(count, () =>

        {

            var t = Array.Find(data, item => item == 900);

        }));

    }

​

    static long DoTest(int count, Action action)

    {

        var sw = Stopwatch.StartNew();

        for (int i = 0; i < count; ++i)

        {

            action();

        }

​

        return sw.ElapsedMilliseconds;

    }

}