Do any of you ladies know if theres a difference between the Similac ready to feed and the powder?…

Do any of you ladies know if theres a difference between the Similac ready to feed and the powder? My little was born 6 weeks early and has had constant issues with feeding she will projective vomiting her whole bottle up most of the time. I decided to try to ready to feed this last time and shes done GREAT on it! Which leads me to believe theres something different about it