Need help with traffic performance between two ports of same NIC

[DannyK]

Hey guys,

for some time i am trying to get full speed from my ISP (2Gb) but i am getting at top around 1.2Gb-1.3Gb. I am trying to figure out exactly, where is bottleneck and if it can be improved to get full 2Gb speed.

This is my current network setup: https://imgur.com/a/bKpCFsC

1, ISP GPON + transceiver is connected to switch Mikrotik CRS310-8g+2s+in SFP+ (1) port
2, Switch Ether ( 8 ) is connected to my custom PC router port with OPNsense and NIC with 4x2.5Gb ports (chip rtl8125b) and act as WAN (RE0) (using realtek-re-kmod 198.00_3 drivers)
3, From custom PC router LAN (RE1) is connected back to switch Ether (7) port
4, From swich to PCs i am using other free ports

I have made sure switch is configured via VLANs (ISP line have its own VLAN on switch and rest of ports have also its own VLAN) and HW offloading so switch is not limiting me.

I did some iperf tests and find out this:
1, From PC (iperf client) to router PC with OPNsense (server) i get 2.35Gb (more or less max port speed)
2, From router PC (iperf client) to public iperf server in my country i get 2Gb (so max speed from ISP)
3, From PC (iperf client) to public iperf server in my country i get 1.2Gb-1.3Gb speed

Based on that i concluded router PC is bottlneck, but i am not sure what exactly is limiting me in speed. In router PC i have i7-6700 CPU @ 3.40GHz (4 cores, 8 threads) which should be fast enough to process 2Gb bandwidth (at least i think). NIC is installed in PCIe 4x slot.

OPNsense is bare metal install:
OPNsense 23.7-amd64
FreeBSD 13.2-RELEASE-p1

I am using basically default install of OPNsense, i have just added interfaces for available ports, defined on WAN ip/gateway (ISP requirement) and Outbound NAT (ISP public ip requirement), for LAN and OPTx i have only autogenerated firewall rules and Default allow LAN to any rule.

I am not using any Zenarmos, IPS, IDS, nothing (at least i am not aware of it, unless something works by default, but didnt enabled explicitly anything).

Does anyone have idea, where could be a problem?

Thanks for help

[DannyK]

In case someone encounter similar issue.

In the end turns out its caused by my Win 11 network settings. I have boot up live ubuntu and in it got full 2Gb speed.

So i need to tune windows network settings.

[DannyK]

Final solution:

Turns out i didnt need to tune much (i have disabled all power saving features on Adapter and Flow Control).

But biggest change made drivers. I have tried several of them. Here is list of them with results:
1, Latest LAN drivers for MOBO (MSI Z390 Tomahawk) from 2022 (+-1.5Gb speed)
2, Latest Win11 Auto Installation Program (NetAdapterCx) - Not Support Power Saving directly from Realtek from 2023/09/27 (+- 1.3Gb speed)
3, Win10 Auto Installation Program (NDIS) - Not Support Power Saving from Realtek from 2023/10/03 (full 2Gb)

Realtek RTL8125 drivers: https://www.realtek.com/en/component/zoo/category/network-interface-controllers-10-100-1000m-gigabit-ethernet-pci-express-software

Leaving it here in case someone else runs into same problem as me.