Animation and FPS

Hey, I've been testing my game on lower end computers and at low FPS (-30) not all frames of the animations are visible, sometime the character's sword is not visible during a swing attack and also doesn't hit since the collider that detect hits is animated with the sword. I'm wondering if this is something that all games suffer from or if there is a solution, i want to make sure that my game is going to behave properly for people with lower end computers. Thanks