Marc-Andre Fleury made 29 saves for his fifth shutout of the season and seventh of his career for Pittsburgh, which is 9-2-1 in its last 12 and now is tied with the New Jersey Devils atop the Atlantic with 96 points.
Gary Roberts had a goal and two assists, Sergei Gonchar added two assists and Evgeni Malkin and Ryan Malone also scored for the Penguins, who moved to within two points of current No. 4 seed Ottawa.
New Jersey, which was off Sunday, holds the tiebreaker over Pittsburgh in the division and has a game in hand.
The Bruins have lost four in a row and seven of nine, and are all but officially eliminated from post-season contention.
The Penguins took control of the game in the first period with three power-play goals.
Malkin gave the Penguins the lead on a slap shot past Boston goalie Tim Thomas while on a 4-on-3 power play with 8:06 left in the opening period. Gonchar and Roberts assisted on the goal, which temporarily tied Malkin with Crosby for the team lead (32).
Crosby retook the team lead about four minutes later when a rebound of a Gonchar shot caromed toward him below the right face-off circle. Crosby whacked it out of mid-air and into the net. The play was reviewed to ensure his stick's contact with the puck was below the crossbar, which it was.
Roberts then scored his 17th while also on the power play when he blasted a slapshot past Thomas from the high slot. Roberts has five points in his last three games.
Before its three-goal burst in 5:24, Pittsburgh had not had three power-play goals in its last six games combined. It had taken 19 periods - plus an overtime period - for the Penguins to accumulate their previous three power-play goals.
Thomas was pulled to begin the second period in favour of Joey MacDonald, who didn't fare much better. Ryan Malone beat him for a short-handed goal 1:09 into the second on the first shot MacDonald faced.
Crosby made it 5-0 with his 34th 4:29 into the final period, eliciting a chant of "M-V-P" from the crowd. He has 111 points, seven more than San Jose's Joe Thornton.
The Penguins are 16-2-1 in their last 19 at home and tied for the third-most victories in club history with 25. Their 43 wins are the most since posting 49 in 1995-96.
Notes: Pittsburgh D Mark Eaton returned to the lineup after not having played since March 1 due to a knee injury. . . . Forty-five of Gonchar's 63 points this season have come on the power play. He is second in the league in scoring by a defenceman and fourth in overall power-play assists. . . . Boston C Marc Savard is third in league in assists with 70, but has gone a season-high five games in a row without one. . . . Pittsburgh rookie C Jordan Staal missed on a chance to match the record for youngest player to score 30 goals. Staal, who has 29 goals, was 18 years, 196 days old Saturday - the same age as Brian Bellows when he scored his 30th for the Minnesota North Stars during the 1982-83 season.