Benchmark.cs

class Benchmark
{
    [Test]
    public void RunTypes()
    {
        var cache = typeof(string).Assembly.GetTypes().ToDictionary(x => x, x => x.Name.Length);
        var sum = 0;
        var sw = Stopwatch.StartNew();
        var n = 1000000;
        for (var i = 0; i < n; i++)
        {
            switch (i % 3)
            {
                case 0:
                    sum += cache[typeof(int)];
                    continue;
                case 1:
                    sum += cache[typeof(string)];
                    continue;
                case 2:
                    sum += cache[typeof(byte)];
                    continue;
                default:
                    throw new Exception();
            }
        }

        Console.WriteLine($"// {DateTime.Today.ToShortDateString()}| sum += cache[typeof(...)] {n:N0} times took: {sw.ElapsedMilliseconds} ms");
        // 2016-02-24| sum += cache[typeof(...)] 1 000 000 times took: 29 ms
    }

    [Test]
    public void RunInts()
    {
        var count = typeof(string).Assembly.GetTypes().Length;
        var cache = Enumerable.Range(0, count).ToDictionary(x => x, x => x);
        var sum = 0;
        var sw = Stopwatch.StartNew();
        var n = 1000000;
        for (var i = 0; i < n; i++)
        {
            sum += cache[i % 3];
        }

        Console.WriteLine($"// {DateTime.Today.ToShortDateString()}| sum += cache[i % 3] {n:N0} times took: {sw.ElapsedMilliseconds} ms");
        // 2016-02-24| sum += cache[i % 3] 1 000 000 times took: 17 ms
    }

    [Test]
    public void RunConcurrentTypes()
    {
        var cache = new ConcurrentDictionary<Type, int>(typeof(string).Assembly.GetTypes().ToDictionary(x => x, x => x.Name.Length));
        var sum = 0;
        var sw = Stopwatch.StartNew();
        var n = 1000000;
        for (var i = 0; i < n; i++)
        {
            switch (i % 3)
            {
                case 0:
                    sum += cache[typeof(int)];
                    continue;
                case 1:
                    sum += cache[typeof(string)];
                    continue;
                case 2:
                    sum += cache[typeof(byte)];
                    continue;
                default:
                    throw new Exception();
            }
        }

        Console.WriteLine($"// {DateTime.Today.ToShortDateString()}| sum += cache[typeof(...)] {n:N0} times took: {sw.ElapsedMilliseconds} ms");
        // 2016-02-24| sum += cache[typeof(...)] 1 000 000 times took: 36 ms
    }

    [Test]
    public void RunConcurrentInts()
    {
        var count = typeof(string).Assembly.GetTypes().Length;
        var cache = new ConcurrentDictionary<int, int>(Enumerable.Range(0, count).ToDictionary(x => x, x => x));
        var sum = 0;
        var sw = Stopwatch.StartNew();
        var n = 1000000;
        for (var i = 0; i < n; i++)
        {
            sum += cache[i % 3];
        }

        Console.WriteLine($"// {DateTime.Today.ToShortDateString()}| sum += cache[i % 3] {n:N0} times took: {sw.ElapsedMilliseconds} ms");
        // 2016-02-24| sum += cache[i % 3] 1 000 000 times took: 25 ms
    }
}

gistfile1.txt

All run in release mode on an old laptop. Win7 .net 4.5.