Well, "fast" is not really a term that is used, but what I consider fast is not what Omega uses. There are generally 3 types of date mechanisms, so a very gradual change that is actually constant speed and changes over a matter of hours. Then there is semi-instantaneous, and instantaneous. The majority of Omega movement do not have an instantaneous date change (like Rolex for example) but use a semi-instantaneous date change. The date will start to change slowly, and then about 1/2 way through the change, when the top of one number and bottom of another number are visible, it will jump fully to the next date. So only part of the change is fast, and the rest is very gradual. This is an instantaneous date change, so what I would consider "fast" anyway... Cheers, Al