Over what time span? The only significant time I remember when both were on IR together was when Crosby got concussed and then Malkin blew his knee apart a few weeks later. They did decent, but ended up getting knocked out fairly early from the playoffs. That was a stretch of a couple months, I have a hard time believing they played .750 hockey from February-April. This was Crosby's first missed game all year so it's more than just this season though if the stat is right. I can't find anything on it via a quick google search, but I didn't look too hard.
I have no idea.... at least 4 games, though, right?