Bring water to a rolling boil in a Dutch oven. Add pasta; cook 10 minutes or until "al dente". Drain.
Melt margarine in pan over medium heat. Add garlic; saute 1 minute. Stir in flour. Gradually add milk, stirring with a whisk until blended; cook until thickened and bubbly (about 8 minutes), stirring constantly. Add 1 cup Parmesan cheese, stirring constantly until it melts.
Rinse pasta well with hot water. Set aside. Add cream cheese to pan; cook over low heat, stirring until it melts. Gradually add cheese sauce to melted cream cheese, stirring constantly.
Add cooked pasta to sauce mixture, tossing well. Spoon into serving dish; top with 1.4 cup Parmesan cheese, parsley, and pepper.