I have a file server with two adapters, both support RSS, running 2012 R2 that has a basic file share.

I have a 8.1 client with two adapters, both support RSS.

When copying files from the server to the client, SMB 3.0 kicks in; however, the maximum data transfer seems to be capped at ~60MB/s (~240Mbps per adapter).

I have not adjusted any configuration settings via PowerShell for any multichannel settings.

It would seem that only half of the 1GB bandwidth of a single adapter is being used across the two interfaces, basically meaning each is only utilizing a quarter of it's full capability.

Why is this happening and how can I correct this?

Hi,

Dozens of factors will affect the transmission speed. The top speed depends on the scarcest resource in the system.

Please use the Resource Monitor to check if any resource is exhausted. From my point of view, it should be the disk. The write speed of a normal hard disk is about 50 - 80 MB/s.

Best Regards.

This drive array (file server) tests at 200+MB/s (RAID 5)

The drive on the workstation storing the data to copy is an SSD... no possible way to tax it more than the network can handle.

I believe there is an issue.. I've tested the same file server against another using MPIO and had transfer speeds on a one nic (2 nic MPIO round/robin) on average over 650Mbps.. 3 times that of the SMB 3.0 speed, on only one of the nics...  nearly 1.3 Gbps total transfer rate.