Peanut Butter Pie

1 graham cracker crust
1 (3 oz.) pkg. cream cheese
1 cup powdered sugar
1 cup peanut butter
1 (9 oz.) container cool whip

Cream together cream cheese, sugar, peanut butter, and 3/4 cup cool whip. Pour into pie crust and cover with remaining cool whip. Chill in refrigerator about 30 minutes.