this is because the m2server needs to load them from the mongen table.. u can quicker it by lowering the size of the table or by putting the mobs u want to m2server to spawn before at the top of the table.. this is all i can say.. another solution is having a quicker cpu but wont change much.. u can gain a few seconds on total loading time but it wont make the loading time go to zero.. sorry (most of the time is dued to the m2server slowness)