Melt the butter in a medium saucepan over medium heat. Add the cream, garlic powder and pepper and simmer for 10-12 minutes or until thick. At the same time bring 4-6 quarts of water to a boil and add the pasta. When the Alfredo sauce has reached your desired consistency, stir in the parmesan cheese. When the pasta is cooked, drain it. Serve the pasta on plates with Alfredo sauce poured over the top.