Structs vs. Classes

Obviously structs are supposedly a lot quicker than classes. However some time ago I heard rumours that in .NET 1.0 some error in the .net framework would cause them to be slower in some cases. Today for some reason I felt like making a small comparison in .NET 2.0.

So, I made a small console program with the following code:

 public struct TestStruct
 {
     public int A;
     public bool B;
     //public string S;
 }

 public class TestClass
 {
     public int A;
     public bool B;
     //public string S;
     public TestClass()
     {
     }
 }

 class Program
 {
     static void Main(string[] args)
     {
         int MaxIterations = 1000000;

         DateTime t1 = DateTime.Now;
         TestStruct[] ts = new TestStruct[MaxIterations];
         for(int i=0;i<MaxIterations;i++)
         {
             ts[i] = new TestStruct();
             ts[i].A = 42;
             ts[i].B = true;
            // ts[i].S = "Hey Joe";
         }
         DateTime t2 = DateTime.Now;
         TestClass[] tc = new TestClass[MaxIterations];
         for(int i=0;i<MaxIterations;i++)
         {
             tc[i] = new TestClass();
             tc[i].A = 42;
             tc[i].B = true;
             //tc[i].S = "Hey Joe";
         }
         DateTime t3 = DateTime.Now;
         TimeSpan ts1 = (TimeSpan) (t2 - t1);
         TimeSpan ts2 = (TimeSpan) (t3 - t2);
         Console.WriteLine("Struct Time: {0} ms", ts1.TotalMilliseconds);
         Console.WriteLine("Class Time: {0} ms", ts2.TotalMilliseconds);
         Console.ReadLine();

     }
 }

I ran it both with the struct/class containing a string, and without.
Here's the results I got from running it (in debug mode):

Structs/Classes without string: 20 ms / 270 ms (= classes are 13,5 times slower than structs)
Structs/Classes with string: 60 ms / 430 ms (= classes are 7 times slower than structs)

The reason I'm trying with and without strings is of course that strings are located on the heap, not on the stack as the other value-types, hence they are quite a bit slower.

It's naturally no surprise that structs are faster than classes - they should be - but it's nice to get an idea of exactly how big a difference there is.