Backup Exec V-Ray edition speed

Hi, I have one VMWare Server with link aggregation 2GB and get 2008AD&Files VM (480GB file size) and 2010 Ex VM (220GB file size) insides it. I create one Windows 2008 R2 VM which install Symantec Backup Exec2014  V-Ray edition with the role of backup exec server in VMWare Server for making backup of 2008AD&Files VM and 2010 Ex VM to one NAS with link aggregation 2GB. The speed is fine and job rate has 4GB or above/mins. When I use one physical server Windows 2008 for backup exec media server to make backup of these 2008AD&Files VM & 2010 Ex VM. This drop to only 5xxMB for AD VM & 1xxxMB for 2010 Ex VM. How can solve?

Best Regards,

YM