Speed Throttled to 9Mbps

[fakebizprez]

My OPNsense server is randomly reducing my network speed from the expected 1Gbps to just 9Mbps.

At first, I suspected the Catalyst 3850 switch was causing the issue, but after bypassing it and connecting directly from the OPNsense server (running on a PowerEdge R730) to my PC using a CAT8 cable, I confirmed that the problem lies with the OPNsense server.

I believe this could be due to a misconfiguration in OPNsense or a BIOS setting that needs adjustment. However, I'm not sure which settings to check. What is the best way to troubleshoot this issue?

BTW - My NIC: Dell Intel X710 Dual Port 10Gb DA/SFP+, + I350 Dual Port 1Gb Ethernet, Network Daughter Card (https://www.dell.com/en-nz/shop/dell-intel-x710-dual-port-10gb-da-sfp-i350-dual-port-1gb-ethernet-network-daughter-card-customer-install/apd/555-bckm/wifi-and-networking)