Ruby was infused with a mere fraction of the gravitonium,
they had virtually no control over their powers. They killed their romantic interest, even though they clearly didn’t want to, and their powers caused all sorts of movement. On the other hand, their personality experienced relatively little change — they still had the same desires; they just had issues with the voices.
By contrast, when
was infused with a much greater quantity, their personality did change dramatically, and they certainly used their powers to hurt people, but they immediately seemed to have much more control. They didn’t kill people upon touching them when they didn’t want to, for example.
What accounts for the much greater control?