If only considering the available number, I think Eb1 and Eb2 could move to current very quickly. USCIS usually wastes many numbers by the end of year if they have not been used by that time because of the handling speed, name checking or whatever. That is why the bill (just failed last Fri) includes the clause which recapture the unused number. But remember that huge application piled on the USCIS desk at the same time would crash their work pace. So the speed and pace will be controlled in the following months. Note that the law only has the max number used for EB and does not have the min number that must be used. So there is no question they can control the moving pace.