You have two databases with identical numbers of hands and identical numbers of players yet the hands are very different? Something does not sound right here.
Zoom databases can take longer to have their caches rebuilt because they often have many more players with 1 or 2 hands or some other small number, which is less common in regular games. For the same number of hands and the same number of players it should take roughly the same amount of time. That the hands are from speed poker or not is immaterial to the cache updating process.