Is there any difference between Customer Enum Type and System Enum Type

Question

I did a test like below ↓

1) Create a customer enum (copy from the dayofweek)

[Serializable]
public enum Tester
{
    // 概要:
    //     Indicates Sunday.
    Sunday = 0,
    //
    // 概要:
    //     Indicates Monday.
    Monday = 1,
    //
    // 概要:
    //     Indicates Tuesday.
    Tuesday = 2,
    //
    // 概要:
    //     Indicates Wednesday.
    Wednesday = 3,
    //
    // 概要:
    //     Indicates Thursday.
    Thursday = 4,
    //
    // 概要:
    //     Indicates Friday.
    Friday = 5,
    //
    // 概要:
    //     Indicates Saturday.
    Saturday = 6,
}

2) Create two test method ...

    static void TestEnumToString()
    {
        var t = Tester.Sunday;
        Enumerable.Range(0, 1000000).ToList().ForEach(i => t.ToString());
    }

    static void DayOfWeekEnumToString()
    {
        var t = DayOfWeek.Sunday;
        Enumerable.Range(0, 1000000).ToList().ForEach(i => t.ToString());
    }

3) Main method

    static void Main()
    {
        Stopwatch sw = new Stopwatch();
        sw.Start();
        TestEnumToString();
        sw.Stop();
        Console.WriteLine("Tester:" + sw.ElapsedMilliseconds);


        sw = new Stopwatch();
        sw.Start();
        DayOfWeekEnumToString();
        sw.Stop();
        Console.WriteLine("DayOfWeek:" + sw.ElapsedMilliseconds);

        Console.ReadKey();
    }

4) The result :

Tester : 3164ms
DayOfWeek : 7032ms

I really don't know why the system type enum is slower than the customer enum type.... Could anybody tell me why ? Thank you...

UPDATE EDIT: Add the [ComVisible(true)] to the enum .

[ComVisible(true)]
[Serializable]
public enum Tester
{
    Sunday = 0,


    Monday = 1,


    Tuesday = 2,


    Wednesday = 3,


    Thursday = 4,


    Friday = 5,


    Saturday = 6,
}

The Result :

Tester : 5018ms
DayOfWeek : 7032ms

The system enum type still slower than the customer enum type...

Answer 1

Enum can be decorate with [ComVisible(true)] or [Flags] and each time it changes the result of your test .

[Serializable]
//[Flags]
[ComVisible(true)]
public enum Tester
{    
  // 概要:
  //     Indicates Sunday.
  Sunday = 0,    

Answer 2

You should add the [ComVisible(true)] attribute if you want to compare apples to apples.