[SOLVED] Fibre connection on one machine averages 500Mbps, but capable of 1000Gbps

[JonnaH_96]

I've had Fibre installed recently which should give around 700-1000Mbps speeds. I've called the engineer out twice to take a look, and this time he replaced the router and it gave him ~800Mbps, however on my own machine plugged into the same cable it gave us 250-400Mbps.

I checked to see whether this was isolated, and used my work laptop - that gave another ~800Mbps speed test. So concluded it must just be my own laptop. Why would this be?

I've tried numberous things which haven't worked, and in some cases made it worse:

1. Disabled all energy saving on ethernet
2. Changed the Jumbo Frame size
3. Disabled Gigabit Lite
4. Disabled 'Auto Disable Gigabit'
5. Changed Speed & Duplex to 1Gbps Full Duplex
6. Changed WOL to 'Not Speed Down'
7. Disabled/Re-enabled network adapter
8. Uninstalled/Reinstalled network adapter
9. Disabled all firewalls
10. Disabled all AV software
11. Checked the router for full duplex compatability (Full Duplex 1000Mbps)
12. Checked network card for transmittion rate (1000Mbps link speed)
13. Checked for any updates (Windows and card)

And possibly more but I can't remember any.

I'm running a Lenovo Legion P5 with a Realtek Gigabit Ethernet card installed, running Windows 11 . The router is a Nokia G-2425G-B GPON Optical Network terminal.

Any thoughts on what else I could try?

 

[bill001g]

Can you change it all to defaults. Things like jumbo frame size will not help on internet that does not support it and it can add overhead. You also need to the leave the port set on auto. You can get strange results when you set the speed on the pc and the router expect to see negotiation because most only support auto mode.

I would first try a USB linux boot image. This will let you run speedtest and see if it is a hardware issue or more likely some strange software issue. The issue tends to be some strange windows setting or maybe some of the bloatware that comes packaged.

You could also try IPERF between 2 machines in your house if you have a second ethernet connected machine. This is a very stupid line mode command that is not affected by things like cpu/memory/disk etc. It pretty much just tests in the nic and the drivers. Most people see 900+mbps in both directions.

 

[JonnaH_96]

Can you change it all to defaults. Things like jumbo frame size will not help on internet that does not support it and it can add overhead. You also need to the leave the port set on auto. You can get strange results when you set the speed on the pc and the router expect to see negotiation because most only support auto mode.

I would first try a USB linux boot image. This will let you run speedtest and see if it is a hardware issue or more likely some strange software issue. The issue tends to be some strange windows setting or maybe some of the bloatware that comes packaged.

You could also try IPERF between 2 machines in your house if you have a second ethernet connected machine. This is a very stupid line mode command that is not affected by things like cpu/memory/disk etc. It pretty much just tests in the nic and the drivers. Most people see 900+mbps in both directions.

SOLVED

Thanks for your reply Bill!

I changed all the defaults of the NIC, then I tried a command I'd seen on a help group, which I didn't expect to work but immediately it jumped from 350Mbps to 1Gbps.

The command was to set the Windows Auto-Tuning Level from 'disabled' to 'normal'. The command was:

netsh int tcp show global

(to show the currect active state of TCP Global Parameters)... mine was showing as disabled, so then I set it to 'normal' using:

int tcp set global autotuninglevel=normal

It was also advised to use ipconfig /flushdns and ipconfig /renew, but I didn't need to do this. I have never heard/used the autotuning command before, I don't have any real idea of what it does, but this outlines my experience pretty well. I'm not sure why my configuration was set as default to 'disabled', as I'm sure this shouldn't be the case, but changing the auto-tuning level stopped the internet speed being throttled straight away.

Thanks!