Question Troubleshooting weird network issue

[mikejs78]

Got a weird issue with my newly-built (Windows 11) PC and network speeds. I am using the onboard ethernet on my Asus ROG Strix X670e-f motherboard; using Oomla's Speedtest, I am only getting ~225 Mbps down and ~600-650 Mbps up, which is much slower than I'm getting other wired connections in my house. I have Verizon FiOS Gigabit internet. Here is my network topology as far as this machine is concerned:

FiOS ONT -> Router (Asus RT-AC88U) -> Wall jack -> Wall jack -> 4-port switch -> Desktop

What's weird is I have a Macbook Pro on that same 4-port switch (connected with an Ethernet to USB-C dongle), and am getting speeds of ~900 Mbps both down and up. I've tried:

* Resetting networking in Windows 11
* Rebooting everything (router, switch, Desktop)
* Swapping ports on the switch
* Swapping ethernet cables (i.e. plugging the Macbook ethernet cable into the desktop)

Note that the ethernet adapter in windows is showing as 1000/1000....

I am at a loss - I feel like there must be some setting in Windows/BIOS/something that is throttling the speeds... I'm usually pretty adept at tracking these types of issues down, but it's the fact that the Macbook and the Desktop have vastly different Anyone have any idea on what to try next?

 

[bill001g]

I would first look for software on your machine that claims to favor one kind of traffic over another. They make all kinds of stupid claims like reducing gaming latency which is mostly not true. This software causes all kinds of strange issues. It tends to be bundled with the bloatware that comes with motherboards and video cards. Asus is one of bigger offenders of bloatware. A common name for this program is cfosspeed.

I doubt it is the problem but you could try to disable IPv6 since that also causes strange issues.

I am somewhat surprised a USB ethernet port on the mac does so well there is a lot of overhead in any USB connection.

I have little knowledge of mac. What you might try first is to transfer files between the mac and the pc with just the switch in between. You can also use a old line mode program called IPERF. That is a very simple programs that is not going to be affected by things like browser versions or disk limitation etc. It tends to just test the drivers and the physical ports.

It is not likely the cable but it could be especially if you are using those flat cables. Flat cables have wires much too small to meet the standard for ethernet. Some machine have a lot of issues with cables that are not certified ethernet cables.

 

[mikejs78]

I did try removing all Asus stuff, and don't see the file you reference... No change. To add a wrinkle, I booted into Ububtu on a USB stick, and ran speedtest from there, and got full 900+ Mbps up/down. So it's definitely a driver/software/Windows issue.

I next tried to boot into safe mode with networking, but for some reason my network driver is not starting in that boot and has a yellow ! saying "this driver was not started because windows booted into safe mode", even though I selected the networking option. There's no option to enable the driver either, it's only option is to disable it.

This is a weird one...

 

[bill001g]

This is where microsoft needs to offer a version of windows for people who are not stupid. That way you can manually check all the things you want installed and leave all the trash not installed.
Hard to say what garbage is causing it. Not likely a simple driver issue but there is a history of defective 2.5g chipsets. Since you board also says it has wifi6e that means it likely was manufactured after intel fixed the issues with the 2.5g chips.
Although it likely will make no difference maybe go to intel (I assume it is a intel ethernet chip) and get the driver from there so you know you have the very newest.

 

[mikejs78]

Tried the newest driver from Intel, still no dice. Really frustrating given that Ubuntu on the same machine has full speed just from a live CD, no fiddling with drivers or settings.

 

[bill001g]

If you have a second machine you can try a old program called IPERF. This is a simple line mode command and it is not affected as much by other software on the machine. It pretty much just checks the hardware and the drivers. Software like cfosspeed that hooks in near the driver level will affect it.

 

[mikejs78]

Tried IPERF connecting from my PC to my Macbook - ~250 Mbps
Tried IPERF connecting from my PC using Ubuntu LiveCD (same machine) to Macbook - ~950 MBps

 

[bill001g]

At some point you get desperate and reinstall windows being very careful about what other software is installed.
I doubt it is a simple driver issue but using iperf has eliminated common things like browser issues or file issues.
That pretty much leave some unkown software. Did you ever install some kind of vpn software. I have had those not uninstall correctly, had to reinstall windows to completely get rid of it. Mine mostly did not work at all rather than being slow.

 

[mikejs78]

@bill001g - thanks for all your help. I hadn't installed any kind of VPN software, so that wasn't it... But, I reinstalled Windows completely and now my bandwidth is back to full speed. I'm still reinstalling all of my applications, but am speed testing after each one in case one of them was the culprit...