Prepare the crust by placing graham crackers in a food processor and pulsing until fine crumbs have formed. Add butter and sugar and pulse until well combined.
Transfer the crumbs to a 9" pie plate. Use a measuring cup to pack down the bottom and your fingers to press the crust firmly to the sides. Set aside.
Filling
In a large mixing bowl, beat together peanut butter and 8 ounces of whipped topping on medium speed until well combined. Add the mixture to the pie crust and spread evenly. Top with remaining 4 ounces of whipped topping. Garnish with peanut butter cups (optional)