I'm not sure exactly what you're asking.
It's really circumstantial. Whoever moves first is decided by their Speed stat, which is partially decided by their Speed IVs, but a Pokemon can still outspeed one with higher Speed IVs than it, if the circumstances are right(higher base Speed, more EVs, etc).
30 Speed IVs and 31 Speed IVs give the same boost to the stat, I believe. so it would still be a speed tie against a Pokemon with that is otherwise identical, but 31 Speed IVs.