Question Slow LAN connection for desktop; possible motherboard issue?

Sep 8, 2022
5
0
10
0
In the past few days, I noticed that my connection speed has dropped considerably. I have 1GIG fiber ethernet, but only getting around 40-50Mbps up and down. (NOW improved to 169 down, 575 up. Still lower than laptop)
So far, I have tried the following to narrow down my issue:
  • Reset router
  • Checked other devices on the network. All are functioning correctly.
  • Hooked a laptop up to the ethernet cable that is typically plugged into desktop, speeds were as expected; about 900Mbps up and down.
  • Uninstalled and reinstalled driver for LAN connection
  • Ensured all windows updates were installed.
  • Virus scanned, no issues
  • Uninstalled Turbo LAN by cFos
  • Uninstalled network adapter, manually reinstalled - Some difference now 169 down, 575 up
  • Installed a WiFi USB adapter, this gave me 34 down, 37 up. Obviously not a viable solution.
  • Disabled Windows being able to "turn off power to device" for "Wake on LAN" feature. No change.
  • checked a setting called autotune. netsh int tcp show global - was set to normal. Disabled - No change. Changed back to "normal"
  • Updated BIOS to newest version. Increased performance - 269 down, 480 up
So, service seems to not be the issue, nor is the cable.

System specs:
  • ASUS TUF Z390 PRO motherboard (non-wifi)
  • i7-9700k
  • Win10 21H2
  • Actiontec T3280 Modem
Decrease in speeds has occurred without any hardware changes. It literally just dropped to 1/20th of normal speeds overnight.
Any ideas greatly appreciated.

Edits: added requested info, added changes, added steps I have taken
 
Last edited:

Lutfij

Titan
Moderator
What BIOS version are you on for your motherboard? Try uninstalling your networking adapter's driver and then manually reinstalling your networking adapter's driver in an elevated command, i.e, Right click installer>Run as Administrator.
 
Sep 8, 2022
5
0
10
0
What BIOS version are you on for your motherboard? Try uninstalling your networking adapter's driver and then manually reinstalling your networking adapter's driver in an elevated command, i.e, Right click installer>Run as Administrator.
BIOS 2804
 
One very strange thing I have notices is if you have wake on lan turned on the port will drop from 1gbit to ether 100mbps or even 10mbps. It normally goes back to 1gbit when the machine is active but I have had mine get stuck at 100mbps although unplugging and replugging the cable fixes that ...as well as turning off the wake on lan function.

I see you got rid of one big offenders CFOSspeed. Did that come with the asus board. They sometimes ship a program with their bloatware called gamerfirst that does the same thing but they may just ship cfos on newer boards.

What tends to be strange on this forum is we see multiple threads in a row that fix a problem with the same thing. 2 different ones today fixed it with autotune. I would check a setting called autotune.
netsh int tcp show global

You want it set to normal....which should be the default. You can try to disable it also but this feature is what used to be called tcp sliding window size and is used to increase the amount of unacknowledged data allowed and helps increase the data transfer speed espeically where high latency is bottlenecking the connection.

Then again it might not be this.

A couple more things you can try is to run IPERF between 2 machines in your house. It is a old line mode command and you should see 900mbps in both directions. This basically tests the hardware and drivers and is not affected by things like web browsers or memory or disk etc. It purely test the network hardware. You can also try to boot a linux usb image. These are designed to run completely from the USB stick and not damage your windows install. They are somewhat limited because everything you run needs to reside on the usb stick. Most do have a web browser installed so you can run standard speedtests. The problem is if the linux image works it just means there is something strange in windows causing it but it will not give you much clue what it is .
 
Sep 8, 2022
5
0
10
0
One very strange thing I have notices is if you have wake on lan turned on the port will drop from 1gbit to ether 100mbps or even 10mbps. It normally goes back to 1gbit when the machine is active but I have had mine get stuck at 100mbps although unplugging and replugging the cable fixes that ...as well as turning off the wake on lan function.

I see you got rid of one big offenders CFOSspeed. Did that come with the asus board. They sometimes ship a program with their bloatware called gamerfirst that does the same thing but they may just ship cfos on newer boards.

What tends to be strange on this forum is we see multiple threads in a row that fix a problem with the same thing. 2 different ones today fixed it with autotune. I would check a setting called autotune.
netsh int tcp show global

You want it set to normal....which should be the default. You can try to disable it also but this feature is what used to be called tcp sliding window size and is used to increase the amount of unacknowledged data allowed and helps increase the data transfer speed espeically where high latency is bottlenecking the connection.

Then again it might not be this.

A couple more things you can try is to run IPERF between 2 machines in your house. It is a old line mode command and you should see 900mbps in both directions. This basically tests the hardware and drivers and is not affected by things like web browsers or memory or disk etc. It purely test the network hardware. You can also try to boot a linux usb image. These are designed to run completely from the USB stick and not damage your windows install. They are somewhat limited because everything you run needs to reside on the usb stick. Most do have a web browser installed so you can run standard speedtests. The problem is if the linux image works it just means there is something strange in windows causing it but it will not give you much clue what it is .
CFOSpeed came with the ASUS board. I didn't see anything called gamerfirst hiding anywhere.

autotune was set to normal. Tried disabling it, no change. Put it back to normal.

I am looking into the IPERF. Will probs try this next.

Also going to try the linux usb image. I can always fresh install windows, I suppose.

Thanks for the suggestions.
 

ASK THE COMMUNITY

TRENDING THREADS