Hi I was investigating the performance hit of creating Cachedependency objects, so I wrote a very simple test program as follows:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Web.Caching;

namespace Test
{
    internal class Program
    {
        private static readonly string[] keys = new[] {"Abc"};
        private static readonly int MaxIteration = 10000000;

        private static void Main(string[] args)
        {
            Debug.Print("first set");
            test7();
            test6();
            test5();
            test4();
            test3();
            test2();
            Debug.Print("second set");
            test2();
            test3();
            test4();
            test5();
            test6();
            test7();
        }

        private static void test2()
        {
            DateTime start = DateTime.Now;
            var list = new List<CacheDependency>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(new CacheDependency(null, keys));
            }

            Debug.Print("test2 Time: " + (DateTime.Now - start));
        }

        private static void test3()
        {
            DateTime start = DateTime.Now;
            var list = new List<Func<CacheDependency>>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(() => new CacheDependency(null, keys));
            }

            Debug.Print("test3 Time: " + (DateTime.Now - start));
        }

        private static void test4()
        {
            var p = new Program();
            DateTime start = DateTime.Now;
            var list = new List<Func<CacheDependency>>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(p.GetDep);
            }

            Debug.Print("test4 Time: " + (DateTime.Now - start));
        }

        private static void test5()
        {
            var p = new Program();
            DateTime start = DateTime.Now;
            var list = new List<Func<CacheDependency>>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(() => { return p.GetDep(); });
            }

            Debug.Print("test5 Time: " + (DateTime.Now - start));
        }

        private static void test6()
        {
            DateTime start = DateTime.Now;
            var list = new List<Func<CacheDependency>>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(GetDepSatic);
            }

            Debug.Print("test6 Time: " + (DateTime.Now - start));
        }

        private static void test7()
        {
            DateTime start = DateTime.Now;
            var list = new List<Func<CacheDependency>>();
            for (int i = 0; i < MaxIteration; i++)
            {
                list.Add(() => { return GetDepSatic(); });
            }

            Debug.Print("test7 Time: " + (DateTime.Now - start));
        }

        private CacheDependency GetDep()
        {
            return new CacheDependency(null, keys);
        }

        private static CacheDependency GetDepSatic()
        {
            return new CacheDependency(null, keys);
        }
    }
}

But I can't understand why these result looks like this:

first set
test7 Time: 00:00:00.4840277
test6 Time: 00:00:02.2041261
test5 Time: 00:00:00.1910109
test4 Time: 00:00:03.1401796
test3 Time: 00:00:00.1820105
test2 Time: 00:00:08.5394884
second set
test2 Time: 00:00:07.7324423
test3 Time: 00:00:00.1830105
test4 Time: 00:00:02.3561347
test5 Time: 00:00:00.1750100
test6 Time: 00:00:03.2941884
test7 Time: 00:00:00.1850106

In particular: 1. Why is test4 and test6 much slower than their delegate version? I also noticed that Resharper specifically has a comment on the delegate version suggesting change test5 and test7 to "Covert to method group". Which is the same as test4 and test6 but they're actually slower? 2. I don't seem a consistent performance difference when calling test4 and test6, shouldn't static calls to be always faster?