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.