saveAll gotcha (Cake v1.3.6)

Could anybody clarify this from the CakePHP 1.3 docs “Calling a saveAll before another saveAll has completed will cause the first saveAll to return false. One or both of the saveAll calls must have atomic set to false to correct this behavior.”

I have an app (an old 1.3 app that I am adding functionality to) that will collect responses from about 200 people over an hour. At the end of the hour all the forms will be saved simultaneously and currently each person’s responses are saved with a saveAll.

Does this mean that 199 of my simultaneous saveAlls are going to fail and return false? If so does setting atomic=false fix that? If that’s the case what are the disadvantages of setting atomic=false all the time??

Appreciate any insight.