Hello,
For some very bizzare reason, the Intel Ethernet refuses to upload to the internet at the correct speed (note LAN traffic operates at 2.5Gbit as intended), resulting in around 300-400mbit versus my 900mbit line speed.
However, if the Intel ethernet device via device manager is forced to 1Gbit, the speed is 900/900 to the WAN as expected.
Things ruled out:
- It is specific to this motherboard. I have multiple devices on my network at 2.5Gbit, none of which exhibit this WAN upload speed issue.
- It is not specific to Windows 10. I have confirmed this is also an issue on Linux. Forcing to 1gbit on both OSes resolves the problem.
- Forcing the NIC to be 1gbit full duplex negotiation resolves the problem, the WAN line speed is 900/900 which speed tests consistently hit when forced into 1Gbit. It has issues when set to 2.5gbit full duplex.
- I want to stress again, LAN traffic device to device operates properly at 2.5Gbit. It is purely a WAN issue.
- My router (UniFi Cloud Gateway Max) has no special settings for this device, which is ruled out anyway because of the 1Gbit "resolution".
- I have rolled the NIC's drivers back a version, no change.
- I have consulted ChatGPT and tried many things to fix the issue such as enforcing a QoS policy, TCP auto-tuning disabled / enabled, Flow control enabled / disabled, Safe Boot, many things.
I am on BIOs version 2904, AGESA 1.2.0.3a. Exact motherboard model is ROG Strix x670E-E GAMING WIFI.
The network controller is a Intel Ethernet Controller (3) I225-V, driver version 1.1.4.43.
