[SOLVED] Gbit Network Connection getting capped at 200-300 Mbit/s by Windows

[philipp.arv]

Around 2 weeks ago i upgraded from a 400mbit to a gbit connection. Everything worked fine.

My PC:
ASUS P6X58D-E (support gbit speeds)
Intel Xeon x5675 @4.2GHz

Network:
FRITZ!Box 6591 Cable
EdgeRouter X (setup as switch)

Now the problem:
My PC is getting capped at 200-300 Mbits. All the networks settings are correct. I found out that the ERX had a offloading feature that needs to be activated in order to reach higher speeds.
And look at that that did the trick and now the best part: After 2 or 3 days i felt the internet was getting bit slower so i just made a speedtest and i was back down to 200-300 Mbits even with the offloading settings on. Now it seems like the offloading features won't effect anything but i still left them on.

I've tested with a debian distro and i reached gbit speeds without any problem so there is a windows issue now the problem is what is there i can do without resetting my whole PC and reinstall everything.

What i have tried:
Reinstalling drivers in safe mode (althought this was kinda buggy, nothing changed)
Resetting all network settings via Windows Settings Tab and via CMD

I have no idea what to try next, is there anthing else to try or to look up maybe.

Thanks alot!

 

[Grobe]

Try to see if you can get an older driver for your network card.

 

[SamirD]

Try connecting directly to the fritz box and see if that changes anything.

 

[philipp.arv]

Try to see if you can get an older driver for your network card.

I have tried that before but didn't work, newest or older drivers,

Try connecting directly to the fritz box and see if that changes anything.

Forgot to mention it. But i tried that aswell. And by the way connecting a different device on my exact same port works.

 

[Arthianne]

I tried linux and found it was a window setting, I fixed it using command prompt with the code: netsh int tcp set global autotuninglevel=normal

And this resolved my issue, I'm now getting almost 800 down, which is double what I'm paying for so i cant complain, thank you so much.

 

[Arthianne]

if its already set to normal do the same command line but disable it instead so it would be : netsh int tcp set global autotuninglevel=disabled

 

[philipp.arv]

if its already set to normal do the same command line but disable it instead so it would be : netsh int tcp set global autotuninglevel=disabled

IT WORKS!!! "netsh int tcp set global autotuninglevel=normal" did the trick for me!

It was set to disabled and by setting it to normal i now get gbit speeds.

Thank you so much!

 

[philipp.arv]

I just tried the solution on a different device at home but the autotuninglevel thing doesnt seemt to have any big effect. I tried the same things as before. But in debian it is reaching 200-300 Mbits aswell.
I also tried with a USB-3.0 adapter and the device is able to reach gbit speeds.

The PC has a ASUS Sabertooth X58 motherboard and a onboard gbit ethernet from Realtek.
Drivers are also uptodate.

Any other solutions to try or do you think the onboard nic is broken in some way.

 

[SamirD]

I just tried the solution on a different device at home but the autotuninglevel thing doesnt seemt to have any big effect. I tried the same things as before. But in debian it is reaching 200-300 Mbits aswell.
I also tried with a USB-3.0 adapter and the device is able to reach gbit speeds.

The PC has a ASUS Sabertooth X58 motherboard and a onboard gbit ethernet from Realtek.
Drivers are also uptodate.

Any other solutions to try or do you think the onboard nic is broken in some way.

Try one more linux live cd (different one) and if it is also getting 200-300Mbit, we're going to need to check the cable and the port on the router with another device that's working properly.

 

[SamirD]

IT WORKS!!! "netsh int tcp set global autotuninglevel=normal" did the trick for me!

It was set to disabled and by setting it to normal i now get gbit speeds.

Thank you so much!

Seems like this is a common problem as of recently--thank you for confirming that it fixed it!

 

[bill001g]

Maybe microsoft put a "fix" in one of their latest patches that changed this

 

[philipp.arv]

Try one more linux live cd (different one) and if it is also getting 200-300Mbit, we're going to need to check the cable and the port on the router with another device that's working properly.

Ports are all good. I have no faulty cables aswell. Like i said via a usb 3.0 ethernet adapter i can reach gbit speeds. I'll open the pc and look at the onboard nic just in chase.

 

[SamirD]

Ports are all good. I have no faulty cables aswell. Like i said via a usb 3.0 ethernet adapter i can reach gbit speeds. I'll open the pc and look at the onboard nic just in chase.

I wouldn't open the case as you probably won't find anything and instead look into the ethernet port with a flashlight for anything unusual. If there's enough packet retransmits then you can have a gigabit link and the speeds you're getting, and that could be attributed to something physically not working right.

 

[swanthony]

I had a bizarre situation where I was getting:

• Allo ISP, hardwired, Desktop, Windows 7 - Full speeds
• Allo ISP, hardwired, Laptop, Windows 10 - Full speeds
• Spectrum ISP, hardwired, Desktop, Windows 7 - 1/4 download bandwidth, full upload bandwidth
• Spectrum ISP, hardwired, Laptop, Windows 10 - Full speeds

Enabling Receive Window Auto-Tuning on the Windows 7 Desktop fixed it for me (i.e. netsh int tcp set global autotuninglevel=normal ). So thank you!

What still leaves me scratching my head is why I was getting full bandwidth on the desktop with one ISP but not the other. What in the world does the ISP have to do with why turning on Window Auto-Tuning would help?? Anyone have any thoughts?

 

[SamirD]

What still leaves me scratching my head is why I was getting full bandwidth on the desktop with one ISP but not the other. What in the world does the ISP have to do with why turning on Window Auto-Tuning would help?? Anyone have any thoughts?

That's definitely a head scratcher. The only thing I could think of is related to MTU, but adjusting that should be automatic per tcpip specs.

 

[mkdr]

Wanted to post on here so people see this. I think there is a bug of the TCP receive window algorithm / autotuning for USB gbit adapter. I have 4 adapter here, 3 by Realtek one by ASIX, and they all show a bugged behavior on all my Windows 10 and 11 PCs, regardless what drivers I use. The randomly get broken and are stuck at around 5MB/s, then when you wait and start downloads they get up to 1gbit but then slow down again to under 10MB/s. I can easily reproduce this issue on all my PCs.

I had the same issue on an older Broadcom chip and bought a new PCIe Realtek card and this one also had the issue, until I deactivated all offload settings in the driver settings. My theory is that there is some bug either in Windows or the drivers, and it is worse for USB Gbit adapters.