I discovered that when you are slicing multiples of the same part (such as 20 copies of the same small part, on the tray at once), that if you first slice just one part by itself, which is quick, then when you multiply the part to the number you need and slice again, it only take the same amount of slicing time as the single part did.
I think what it's doing is that it knows that multiples of the same part will have about the same slice, so it just remembers the single-part slice, and uses it over and over, only adding travels between the parts. This of course would mean that the starting and ending points would be the same on every part, if it matters, whereas if you multiplied the parts first and then sliced, the starting and ending points of each part might move around.
