Slow ethernet speeds with NetworkManager. seemingly limited speed.

Morriswell · 2025-04-28 21:34:18

Hey there! I have had some issues with my wired ethernet speed for some time now, and have finally decided to fix it. We just switched to a 1100 mbps plan, however my computer is limited to just under 100 mbps. I recall but can not prove that in january when I installed arch on this pc, I was getting 980 mbps, and I know for sure that before then when I was on windows I was getting those speeds. I am using a cat-6 ethernet cable and my motherboard is limited to 2.5 gbps. I am using Network manager with kde plasma 6.
Some things I have tried: I re-installed network manager. I installed ethtool(can limit speed below 100 mbps, but even setting it to 1000 does not change speed.) tested duplex half and duplex full. turned autoneg on and off. Tested on different computers(archlinux laptop had same ethernet speeds but 300mbps wifi. Fedora computer worked fine with ethernet at 600mbps).
here is some information about the setup

sudo ethtool eno1
[sudo] password for morriswell: 
Settings for eno1:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
                                             1000baseT/Full
        Link partner advertised pause frame use: Symmetric
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 1000Mb/s
        Duplex: Full
        Auto-negotiation: on
        master-slave cfg: preferred slave
        master-slave status: slave
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        MDI-X: Unknown
        Supports Wake-on: pumbg
        Wake-on: d
        Link detected: yes

here is ip a command

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute 
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:bf:b8:3f:fe:31 brd ff:ff:ff:ff:ff:ff
    altname enp7s0
    altname enx08bfb83ffe31
    inet 10.0.0.223/24 brd 10.0.0.255 scope global dynamic noprefixroute eno1
       valid_lft 171139sec preferred_lft 171139sec
    inet6 2601:601:a402:a510::add2/128 scope global dynamic noprefixroute 
       valid_lft 171749sec preferred_lft 171749sec
    inet6 2601:601:a402:a510:1204:6d70:546:a384/64 scope global dynamic noprefixroute 
       valid_lft 300sec preferred_lft 300sec
    inet6 fe80::e4a6:486d:5493:3eea/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

my lspci result for the ethernet controller:

 07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller (rev 05)

when I run sudo dmesg grep

 $ sudo dmesg | grep r8169
[   71.211702] r8169 0000:07:00.0: enabling device (0000 -> 0003)
[   71.211827] r8169 0000:07:00.0: can't disable ASPM; OS doesn't have ASPM control
[   71.218208] r8169 0000:07:00.0 eth0: RTL8125B, 08:bf:b8:3f:fe:31, XID 641, IRQ 179
[   71.218212] r8169 0000:07:00.0 eth0: jumbo features [frames: 9194 bytes, tx checksumming: ko]
[   71.220055] r8169 0000:07:00.0 eno1: renamed from eth0
[   72.523426] Realtek Internal NBASE-T PHY r8169-0-700:00: attached PHY driver (mii_bus:phy_addr=r8169-0-700:00, irq=MAC)
[   72.654760] r8169 0000:07:00.0 eno1: Link is Down
[   75.272224] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 1059.918493] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 3982.500213] r8169 0000:07:00.0 eno1: Link is Down
[ 3985.939018] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4031.536708] r8169 0000:07:00.0 eno1: Link is Down
[ 4034.410493] r8169 0000:07:00.0 eno1: Link is Up - 10Mbps/Full - flow control rx/tx
[ 4065.104517] r8169 0000:07:00.0 eno1: Link is Down
[ 4067.843732] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4132.142774] r8169 0000:07:00.0 eno1: Link is Down
[ 4138.146097] r8169 0000:07:00.0 eno1: Link is Down
[ 4141.574029] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4141.576729] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4143.032418] r8169 0000:07:00.0 eno1: Link is Down
[ 4149.039764] r8169 0000:07:00.0 eno1: Link is Down
[ 4152.352480] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4152.355026] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4236.282624] r8169 0000:07:00.0 eno1: Link is Down
[ 4239.691519] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 4382.000781] r8169 0000:07:00.0 eno1: Link is Down
[ 4385.539114] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control off
[ 4406.368848] r8169 0000:07:00.0 eno1: Link is Down
[ 4409.987688] r8169 0000:07:00.0 eno1: Link is Up - 1Gbps/Full - flow control rx/tx

and lastly a neofetch output if that is of any use:

  neofetch
                   -`                    morriswell@OscarsarchgamingPC 
                  .o+`                   ----------------------------- 
                 `ooo/                   OS: Arch Linux x86_64 
                `+oooo:                  Kernel: 6.14.4-arch1-1 
               `+oooooo:                 Uptime: 1 hour, 40 mins 
               -+oooooo+:                Packages: 1130 (pacman) 
             `/:-:++oooo+:               Shell: bash 5.2.37 
            `/++++/+++++++:              Resolution: 1600x900, 2560x1440 
           `/++++++++++++++:             DE: Plasma 6.3.4 
          `/+++ooooooooooooo/`           WM: KWin 
         ./ooosssso++osssssso+`          Theme: Breeze-Dark [GTK2], Breeze [GTK3] 
        .oossssso-````/ossssss+`         Icons: breeze-dark [GTK2/3] 
       -osssssso.      :ssssssso.        Terminal: konsole 
      :osssssss/        osssso+++.       CPU: 13th Gen Intel i5-13600K (20) @ 5.100GHz 
     /ossssssss/        +ssssooo/-       GPU: AMD ATI Radeon RX 6700/6700 XT/6750 XT / 6800M/6850M XT 
   `/ossssso+/:-        -:/+osssso+-     GPU: Intel Raptor Lake-S GT1 [UHD Graphics 770] 
  `+sso+:-`                 `.-/+oso:    Memory: 5292MiB / 31826MiB 
 `++:.                           `-/+/
 .`                                 `/

As I stated earlier, I think it is an arch issue as when running my fedora pc ethernet was fast, but either of my arch pc's were slow and even the wifi was faster on the arch laptop. I do have work and school throught the week, but I would make sure to respond as quickly as possible. Thank you!

espresso · 2025-04-29 05:00:59

edit: not 8168 chip

If an ASPM issue with RealTek NIC or mainboard, it can often be disabled in UEFI/BIOS, or by adding "pcie_aspm=off" to the https://wiki.archlinux.org/title/Kernel_parameters

Last edited by espresso (2025-04-29 15:36:09)

seth · 2025-04-29 06:54:53

This isn't a 8168 chip, but RTL8125 - and the third thread about the chip
https://bbs.archlinux.org/viewtopic.php?id=304931
https://bbs.archlinux.org/viewtopic.php?id=305216

seth · 2025-05-01 06:53:32

https://bbs.archlinux.org/viewtopic.php … 2#p2239472 hinges on eee

Morriswell · 2025-05-06 06:21:39

Hey there, Sorry for the late reply, I have had a lot of college acceptance/ final high school stuff to do. I do not want to waist y'all's time because I know that you guys are helping out of the goodness of your hearts. I tried the aspm off changes, with little to no change in Ethernet speed. For your first comment Seth, I know it is not a hardware issue. I ran it on 2 arch computers and had the same issue, but on my fedora laptop I got higher speeds. Specifically, on my wi-fi capable laptop(arch) I could get faster wifi than Ethernet. The fedora OS laptop got faster Ethernet. I think the weirdest thing is it only follows my arch installs, but not fedora.
In regards to your second message, I tried the "sudo ethtool --set-eee en0o1 eee off" and nothing changed.
Specifically, The Ethernet is not necessarily limited to exactly 100 Mbps, but around 88 to 94, and the upload speed is often higher than the download, but never above 100. I am using network manager for my Ethernet connections on both devices, so in the meantime while I wait for a reply, I am going to test a new arch install using something other than network-manager.

Thank you all for your help so far, I am sorry it took so long to reply, I do not mean to waist your time.

seth · 2025-05-06 07:47:26

https://bbs.archlinux.org/viewtopic.php?id=305277 uses https://aur.archlinux.org/packages/r8125-dkms
What module do you end up using on fedora?

Fwwi:

not necessarily limited to exactly 100 Mbps, but around 88 to 94

Your device flickers and at some point was downshifted to 10MBps - also just because you downshift doesn't mean you still get hat limit, it just means "the signal is way to bad for the current speed".
So this doesn't indicate much.

Morriswell · 2025-05-08 17:31:09

Holy heck bro, I am working through some stuff with my therapist rn, is there a way to mark this as like postponed, or temporarily abandoned? I really can't do this right now, but I don't want to waist y'alls time

seth · 2025-05-08 20:39:40

You can just deal with your situation and pick this up later on. There's no need to indicate afk. It's implied.

Arch Linux

#1 2025-04-28 21:34:18

Slow ethernet speeds with NetworkManager. seemingly limited speed.

#2 2025-04-29 05:00:59

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#3 2025-04-29 06:54:53

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#4 2025-05-01 06:53:32

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#5 2025-05-06 06:21:39

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#6 2025-05-06 07:47:26

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#7 2025-05-08 17:31:09

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

#8 2025-05-08 20:39:40

Re: Slow ethernet speeds with NetworkManager. seemingly limited speed.

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