If you have an N64 you must get an Expansion Pak. The Expansion Pak increases the graphics and the speed of some of the newers games on the N64. Some of the newest one's will not play with out it. Like some people have said this is just like adding RAM to a PC. It's easy and fast and I've had no problems with mine. If you have an N64 buy an expansion pak. You will not regret it.