This article provides an answer to the query: Can GFI MailEssentials handle a high volume of messages?
Since the architecture of GFI MailEssentials is very scalable, the product can easily handle more than 100,000 messages daily.
When having more than 100,000 messages, however, it is recommended to separate the load by using separate GFI MailEssentials servers for inbound emails and for outbound emails.
Note that MailEssentials 2015 SR1 and previous versions could process five (5) emails per second. MailEssentials 20 introduces multithreading that allows twenty (20) to twenty-five (25) emails to be processed per second, depending on the number of CPUs available.