Backup Exec Speeds

I have Backup Exec 2012 running in an environment to back up a couple physical servers and about 20 virtual servers running in a VMWare cluster with vCenter.

Backup speeds seem very slow.  400 to 550 MB/min seems to be the top speed that I will get.  Everything is plugged into GB ports on Cisco switches.

I turned off the "Checkpoint Restart" hoping that would make a difference but it didn't.

Here are my questions:

1)  Are there any other items I should check to try to improve speed?

2)  What are expected backup rates for servers connected to a GB network?  I thought I remembered getting 1.5 to 2 GB/min at my last job but maybe I'm just being crazy.    

Thanks