Sending speeds are directly relational to your server, resources at time of sending, and your recipients. This knowledge base article lists some of the factors in your 1-2-All mailings and in your server configuration that will determine the sending speed you experience.
The following is a list of 1-2-All configuration recommendations for ensuring top sending speed:
Upgrade 1-2-All to the latest version
Schedule mailings to be sent late at night
Do not use sending filters
Use minimal personalization
Adjust mail sending delay settings, under Settings->Script Settings.
Ensure your cronjobs are setup
Minimize the size of the emails and attachments you are sending.
The following is a list of server related considerings you may want to discuss with your server administrator or web host to ensure your server is sending at top speed:
