To better determine performance, I shut down unnecessary services (e.g., file sharing) on my host machine during testing. To establish a baseline, I sent out my 4303 messages without using any antivirus software; Microsoft Exchange Server delivered all the messages in 27 minutes. I then installed each product, sent my test messages, then repeated the test and recorded the best delivery time out of the two passes. I also ran an additional test on Sybari Antigen for Microsoft Exchange, changing its bias to Favor Certainty, which gives more importance to accuracy over performance. I used the Exchange Message Tracking logs to determine delivery times. Your production servers will probably see much smaller performance differences than I did in my test environment, which ran the products on virtual machines.

Table A: Performance

	CA eTrust Antivirus Exchange Option*	McAfee Active Mail Protection	Symantec Mail Security	Sybari Antigen (defaults**)	Trend Micro ScanMail Suite
Time to deliver all messages	1 hour, 21 minutes	4 hours, 13 minutes	2 hours, 31 minutes	4 hours, 29 minutes**; 5 hours, 20 minutes***	35 minutes

* Using InoculateIT
** Using normal bias (at least two engines)
*** Using Favor Certainty bias (two to three engines)