10 G Networking slow

I have the following hardware:
Dell 6248, 2848
HP 1810-48G J9660A, HP A5820X JC202A
2 x HP DL380P G8 with 2x 10G ethernet LOM ports using DAC connected to the JC202A (teamed windows server)
Workstation with  X520-DA2 connected to JC202A

iperf3 Stats Server 1 to workstation
Accepted connection from 192.168.1.201, port 49962
[  5] local 192.168.1.213 port 5201 connected to 192.168.1.201 port 49963
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   160 MBytes  1.35 Gbits/sec
[  5]   1.00-2.00   sec   170 MBytes  1.42 Gbits/sec
[  5]   2.00-3.00   sec   136 MBytes  1.14 Gbits/sec
[  5]   3.00-4.00   sec   172 MBytes  1.44 Gbits/sec
[  5]   4.00-5.00   sec   168 MBytes  1.41 Gbits/sec
[  5]   5.00-6.00   sec   169 MBytes  1.41 Gbits/sec
[  5]   6.00-7.00   sec   153 MBytes  1.28 Gbits/sec
[  5]   7.00-8.00   sec   165 MBytes  1.39 Gbits/sec
[  5]   8.00-9.00   sec   172 MBytes  1.44 Gbits/sec
[  5]   9.00-10.00  sec   173 MBytes  1.45 Gbits/sec
[  5]  10.00-10.02  sec  3.01 MBytes  1.37 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.02  sec  1.60 GBytes  1.37 Gbits/sec                  receiver

Server 2 to workstation
PS D:\Downloads\iperf3.9_64> .\iperf3.exe -c 192.168.1.213
Connecting to host 192.168.1.213, port 5201
[  5] local 192.168.1.242 port 50018 connected to 192.168.1.213 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   144 MBytes  1.21 Gbits/sec
[  5]   1.00-2.00   sec   156 MBytes  1.31 Gbits/sec
[  5]   2.00-3.00   sec   158 MBytes  1.33 Gbits/sec
[  5]   3.00-4.00   sec   164 MBytes  1.38 Gbits/sec
[  5]   4.00-5.00   sec   157 MBytes  1.31 Gbits/sec
[  5]   5.00-6.00   sec   161 MBytes  1.35 Gbits/sec
[  5]   6.00-7.00   sec   167 MBytes  1.40 Gbits/sec
[  5]   7.00-8.00   sec   159 MBytes  1.34 Gbits/sec
[  5]   8.00-9.00   sec   163 MBytes  1.37 Gbits/sec
[  5]   9.00-10.00  sec   164 MBytes  1.37 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.00  sec  1.56 GBytes  1.34 Gbits/sec                  sender
[  5]   0.00-10.03  sec  1.56 GBytes  1.33 Gbits/sec                  receiver

server 2 <> Server 1 10Threads

[SUM]   0.00-10.00  sec  8.89 GBytes  7.64 Gbits/sec                  sender
[SUM]   0.00-10.02  sec  8.88 GBytes  7.61 Gbits/sec                  receiver
Server 2 to Workstation 10 Threads
[SUM]   0.00-10.00  sec  1.21 GBytes  1.04 Gbits/sec                  sender
[SUM]   0.00-10.02  sec  1.21 GBytes  1.04 Gbits/sec                  receiver

Server 1 to Workstation 10 Threads
 ID] Interval           Transfer     Bitrate
[  5]   0.00-10.00  sec  1.41 GBytes  1.21 Gbits/sec                  sender
[  5]   0.00-10.02  sec  1.41 GBytes  1.21 Gbits/sec                  receiver