How do you increase the speed of your PS2?

I was trying to play Kingdom Hearts II the other day, and I noticed that the load times on the game had increased dramatically. I don't know if its just the age of my PS2, because its like 7 years old, or if its memory buildup somewhere. Either way, I would love to play Kingdom Hearts II and catch up before the release of III and not have to sit and wait to go into Port Royal for 5 minutes between each location.