Strange Network Behavior in VM

Hi,

I have a 10Gbps network environment. When I use iperf3 from my machine --> Unraid, I get the following output.

PS C:\iperf3> .\iperf3.exe -c 192.168.9.248 -p 5201
Connecting to host 192.168.9.248, port 5201
[  4] local 192.168.9.51 port 51406 connected to 192.168.9.248 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   557 MBytes  4.67 Gbits/sec
[  4]   1.00-2.00   sec   539 MBytes  4.52 Gbits/sec
[  4]   2.00-3.00   sec   567 MBytes  4.76 Gbits/sec
[  4]   3.00-4.00   sec   516 MBytes  4.33 Gbits/sec
[  4]   4.00-5.00   sec   543 MBytes  4.56 Gbits/sec
[  4]   5.00-6.00   sec   562 MBytes  4.71 Gbits/sec
[  4]   6.00-7.00   sec   555 MBytes  4.66 Gbits/sec
[  4]   7.00-8.00   sec   566 MBytes  4.75 Gbits/sec
[  4]   8.00-9.00   sec   563 MBytes  4.73 Gbits/sec
[  4]   9.00-10.00  sec   574 MBytes  4.82 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  5.41 GBytes  4.65 Gbits/sec                  sender
[  4]   0.00-10.00  sec  5.41 GBytes  4.65 Gbits/sec                  receiver

However, when I use a VM running inside Unraid and use iperf3 --> Unraid server, I get the following output.

PS C:\iperf-3.1.3-win64> .\iperf3.exe -c 192.168.9.248 -p 5201
Connecting to host 192.168.9.248, port 5201
[  4] local 192.168.122.12 port 50413 connected to 192.168.9.248 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  92.9 MBytes   778 Mbits/sec
[  4]   1.00-2.00   sec   106 MBytes   892 Mbits/sec
[  4]   2.00-3.00   sec   112 MBytes   941 Mbits/sec
[  4]   3.00-4.00   sec   111 MBytes   931 Mbits/sec
[  4]   4.00-5.00   sec   110 MBytes   917 Mbits/sec
[  4]   5.00-6.00   sec   110 MBytes   928 Mbits/sec
[  4]   6.00-7.00   sec   113 MBytes   946 Mbits/sec
[  4]   7.00-8.00   sec   111 MBytes   932 Mbits/sec
[  4]   8.00-9.00   sec   109 MBytes   913 Mbits/sec
[  4]   9.00-10.00  sec  98.0 MBytes   823 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  1.05 GBytes   900 Mbits/sec                  sender
[  4]   0.00-10.00  sec  1.05 GBytes   900 Mbits/sec                  receiver

iperf Done.

The Unraid VM is using virtio-net as a network interface and running on bridge mode. I can confirm that the Windows VM detected the network interface and showed 10Gbps.

Two questions

1. In a 10Gbps network configuration, when running iperf3, is it correct to show only 4.65 Gbits/sec for sender and receiver? Or is this only 50% of the speed? (Side notes: when I copy a file, I can copy from the client to the Unraid server at 1GB/sec, which is 10Gbps)

2. Does the link speed between VM and Unraid not exceed 1Gbps? Or is there a setting I am missing somewhere?

Any help would be fantastic!