Clark, who left the game just before the end of the third quarter, had 215 yards on 14-of-23 passing and added 61 yards on the ground. Royster had 141 yards on 17 carries for the Nittany Lions (2-0).
Jordan Norwood led Penn State in receiving with 116 yards and a touchdown.
Lyle Moevao completed 25-of-41 passes for 250 yards but threw two interceptions for the Beavers (0-2). Jacquizz Rodgers accounted for all of Oregon State's scoring, running for 97 yards and two touchdowns.
Beyonce flaunts bikini body, Blue Ivy in vacation pics
Kate Middleton recycles dress at movie premiere