I don't believe .Net 1.1 has a typed array list. I believe there may be something similar in 2.0, but going by a different name. I guess the same thing would be true for collection as far as not being typed, although you can make a collection class by inheriting CollectionBase and using .Add methods to restrict your type. But as far as collections and arraylists, they both have different options. Collections can be keyed, which would probably added up to more overhead, although you may not notice a speed decrease at all. You'll just have to test it.