Performance of foreach vs. List.ForEach

Today I was iterating a List<int> using a foreach-loop and feeling a bit smug in knowing how much more performance-conscious I was being than if I'd tried doing the same thing with an ArrayList filled with ints. Thanks to the wonder of generics, the C# compiler neatly avoids numerous boxing operations by using a System.Collections.Generic.IEnumerator<int> instance instead of the older System.Collections.IEnumerator. Then I got to thinking: "is this really the fastest way?" Upon investigation, it turns that, no, it isn't the fastest way.