Many people aren’t aware of how important the Network Interface Card (NIC) in their system really is. If you picture your database as a warehouse, the NIC devices are the doors and bays where stuff comes in and out. Imagine if you had one door, and everyone from employees to customers and deliveries came into that one door! that’s what’s happening on your SQL Server, right now.
Of course, a modern NIC can handle a lot of traffic – equivalent to a really big door. But do you really know if it is “big enough”? If you toss some monitoring on there, you might find that things have to wait on the network stack from time to time.
One way to mitigate this issue is to add another NIC into your system, give it a separate IP address, and do all of your backups, transfers, and any other maintenance work on that IP. If you separate out this traffic from the primary NIC, you’ll possibly gain some speed. If you’re on a cluster, you already have two NIC’s in your system (or should have) for the heartbeat, but what I’m advocating here is a dedicated NIC for maintenance.