We have a couple different speed options when sending a campaign they are as follows:
                                        15 Emails per hour
                                        30 Emails per hour
                                        60 Emails per hour
                                        120 Emails per hour
                                        500 Emails per hour
                                        1000 Emails per hour
                                        1500 Emails per hour
                                        3000 emails per hour
                                        5,000 emails per hour
                                        10,000 emails per hour
                                        20,000 emails per hour
                                        40,000 emails per hour
                                        50,000 emails per hour
                                        
                                        Keep in mind you want to start slow and warmup the ip's before sending very high volumes.
                                        Also, this is a setting per campaign, and you can schedule multiple campaigns at a time to run.