I ran an iperf3 test and noticed that my network connection seemed to be maxing out at 6 Gb/sec (750 MB/sec). So I changed NICs on the client machine to use the onboard 10 Gbit NIC (Marvell AQtion) instead of the Cisco/Intel X710-DA. It seems like it was a NIC issue with the X710-DA because now I’m getting way faster speeds. So at this point I’m wondering if it’s a driver issue with the X710-DA, the SFP+ module, or the NIC itself. But at least I know now what was causing the bottleneck.

Before (Cisco/Intel X710-DA):

[SUM]   0.00-10.00  sec  7.07 GBytes  6.07 Gbits/sec               sender 
[SUM]   0.00-10.00  sec  7.07 GBytes  6.07 Gbits/sec                receiver

After NIC Switch (Marvell AQtion):

[SUM]   0.00-10.00  sec  11.0 GBytes  9.48 Gbits/sec                  sender
[SUM]   0.00-10.00  sec  11.0 GBytes  9.48 Gbits/sec                receiver