Hi there,
Backup speeds depend on the type of files being backed up. Lots of small files mean that the tape drive doesn't quite reach its full speed when spinning. Its going to have to stop and start constantly.
That said, network speed can also play a role...100MB networks would be far slower than 1GB networks for instance.
So a couple of questions:
1. Is this a local backup, or are you backing up across the LAN?
2. What sort of LAN speed do you have?
3. What type of files are you backing up in your set?
4. Is the backup running at the same time as an antivirus scan for example?
What I have also done is to add 2 tech article links to read through:
http://seer.entsupport.symantec.com/docs/231488.htm
http://seer.entsupport.symantec.com/docs/285756.htm
Laters!