Based on previous input, from one of your engineers: Received Messages are copied multiple times for each address in any received email, resulting in one email becoming many emails before being handed off to the content filter. This allows SPAM that includes multiple addresses to be copied to a new message file for each address before all the messages are handed off to the content filter to be processed over and over again. This is one of the reasons the content filter eats up so much CPU and this should be seen as a big problem. I do not understand why a message would not be passed through the content filter before being copied to multiple files to be processed by the server over and over. It would seem to me that it would be easy for anyone to send one email to the server with every address for the domain, to cause the mail server to replicate the email several hundred times over to be passed through the content filters causing the system resources such as CPU,Disks, to choke rapidly.