Chopping the peanuts in a food processor will give an even texture and make for easy rolling.
Beat peanut butter and butter at medium speed with an electric mixer until creamy; add graham cracker crumbs, beating until blended. Gradually add powdered sugar, beating at low speed until blended. Shape into 1-inch balls, and roll in peanuts. Cover and chill 1 hour. Store in refrigerator.