Throttling Auxiliary Copy Throughput
In some cases auxiliary copy throughput may need to be throttled in order to free up bandwidth for other application data. Use the following DWORD Registry value on MediaAgent for throttling backups and auxiliary copy using that MediaAgent as a destination:
The registry value's data is set to the max MB/hr allowed for each network agent.
So if you enter a value of 150 then throttling will be set to 150 MB/hour.