Backup of VMware virtual machine may take longer time after installed Hotfix 195395.
The VMware backup performance is improved with Backup Exec 2012 Service Pack 2 and Backup Exec 2010 R3 revision 5204 Service Pack 3.
Backup Exec 2012 revision 1798 Service Pack 2
Backup Exec 2010 R3 revision 5204 Service Pack 3
Please also refer to the following document to improve the VMware backup performance.
How to improve VMware backup performance for Backup Exec 2010 R3 with Hotfix 176937 installed