We are running Symantec Backup Exec 2012 patched to the latest version and the job rate is very slow when Symantec Endpoint Protection Virus Scan is enabled on the server.
It can slow from 3-4000Mb per min to 90 - 150Mb per min.
Not only that but the virus scan appears to slow down people accessing files through shared drives.
If I try to perform a copy of 2Gig of data between two servers it can take up to 5-6 minutes when the virus scanner is enabled. Disabled it only takes around 40 seconds.
We are running Endpoint Protection version 12.1.4 but had the same issue running version 12.1.3