Dan Tao

using System;
using System.Diagnostics;

namespace ArrayAllocationTest
{
    class Program
    {
        const int N = 5000;
        const int SmallSize = 10;
        const int MediumSize = 10000;
        const int LargeSize = 10000000;

        static void Main(string[] args)
        {
            int[] array = null;

            Console.WriteLine("Testing small ({0}) array allocation...", SmallSize);
            TimeSpan smallArrayTime = TimeAllocations(ref array, SmallSize, N);

            Console.WriteLine("Testing medium ({0}) array allocations...", MediumSize);
            TimeSpan mediumArrayTime = TimeAllocations(ref array, MediumSize, N);

            Console.WriteLine("Testing large ({0}) array allocation...", LargeSize);
            TimeSpan largeArrayTime = TimeAllocations(ref array, LargeSize, N);

            Console.WriteLine("Small: {0} ms", smallArrayTime.TotalMilliseconds);
            Console.WriteLine("Medium: {0} ms", mediumArrayTime.TotalMilliseconds);
            Console.WriteLine("Large: {0} ms", largeArrayTime.TotalMilliseconds);

            Console.ReadLine();
        }

        static TimeSpan TimeAllocations<T>(ref T[] array, int size, int count)
        {
            long ticks = 0L;

            for (int i = 0; i < count; ++i)
            {
                ticks += TimeAllocation(ref array, size).Ticks;
            }

            return TimeSpan.FromTicks(ticks);
        }

        static TimeSpan TimeAllocation<T>(ref T[] array, int size)
        {
            GC.Collect();

            Stopwatch stopwatch = Stopwatch.StartNew();
            array = new T[size];
            stopwatch.Stop();

            return stopwatch.Elapsed;
        }
    }
}