so it attempt to send all the emails in the one shoot ....
i really prefer if a setting that we edit to set how many email is sent via every job , like 50 email per job , so we will send 600 email per hour . this is can be limited to the emails fetched from the request in cronjob .
from my case, more than 5000 contacts i can't email or try to do it in one shoot . also google, msn, yahoo, they have filter to block ip that use abusive send .