Tyler Shoemaker had 180 yards receiving and two touchdowns for Boise State (6-0, 1-0 Mountain West), which is off to its fourth consecutive 6-0 start.
D.J. Harper added 63 yards and two touchdowns on the ground, while Drew Wright had 79 yards on 16 carries.
Pete Thomas was just 10-of-24 for 100 yards and an interception for the Rams (3-3, 1-1), who've lost three of four after opening the season with consecutive wins.
Chris Nwoke had 74 yards on 15 carries for Colorado State, while Matt Yemm and Joe Brown hauled in the two Ram touchdowns.