Board Thread:Speculation House/@comment-24718692-20140322030224/@comment-24718692-20140322174429

If you look at Weiss and Ruby's fight against Beowolves in the Emerald Forest, Ruby very clearly moves faster than Weiss, appearing to teleport more than move quickly.

As for Weiss appearing to move faster than Ruby while escaping the same fight, that could be as simple as Ruby slowing down to allow Weiss to keep up. If you look, you'll notice that while Weiss was visibly tired after that run, Ruby seemed fine. So either Weiss has incredibly low stamina, Ruby has really high stamina, or Ruby was pulling her punches so to speak.

As for the Death Stalker, that seemed to be more for plot than anything else. Ruby seemed to move at a much reduced speed, seemingly indicating that she was not using her semblance. Weiss likely used her semblance to achieve this speed. One of her glyphs has an appropriate effect.

"One of her earlier and more noticeable abilities is to cast a technique (unofficially) called the "Air Step", in which she creates a glyph which serves as a tangible platform in midair, enabling her to engage in aerial combat with no need to return to ground level. On the other hand, casting the same spell on the ground greatly enhances her speed for a short period of time."

So if we return to your presented example of both characters unable to access their respective speed boosting abilities, I would say that Ruby is the faster of the two.