[SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

yawankels · 2025-08-19 04:55:46

I have been struggling with slow and unstable wifi on my computer, on which I installed Arch about a week ago.

And I mean slow as in around 10 Mbit/s using speedtest-cli. When I had Windows 10 on this thing, the wifi was totally fine (~100 Mbit/s). After I installed Arch, the wifi was as bad as it is now, but swapping out wpa_supplicant and NetworkManager for iwd and systemd-networkd seemed to fix it for a few days, but now it's back in the pits.

My network runs through Adguard Home and Unbound, but I have confirmed it's not a DNS issue. networkd and resolved are both set up, and no matter which power saving features I disable, no matter what band I use, the wifi will not work as it did on Windows.

My wifi is a MEDIATEK Corp. MT7921K (RZ608) Wi-Fi 6E 80MHz, built-in to the motherboard. I am running KDE Plasma on Wayland as my desktop.

Any help would be appreciated.

Last edited by yawankels (2025-08-20 18:10:20)

seth · 2025-08-19 08:11:44

Please post your complete system journal for the boot:

sudo journalctl -b | curl -F 'file=@-' 0x0.st

Please post the output of

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

Please post the output of

iw dev wlan0 link # wlan0 speculates on the actual device name
iw dev wlan0 station dump

yawankels · 2025-08-19 18:13:25

seth wrote:

Please post your complete system journal for the boot:
sudo journalctl -b | curl -F 'file=@-' 0x0.st

http://0x0.st/KsVP.txt

seth wrote:

Please post the output of

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

dbus-org.freedesktop.network1.service    | system
dbus-org.freedesktop.resolve1.service    | system
dbus-org.freedesktop.timesync1.service   | system
display-manager.service                  | system
getty@tty1.service                       | getty.target.wants
iwd.service                              | multi-user.target.wants
nvidia-hibernate.service                 | systemd-hibernate.service.wants
nvidia-resume.service                    | systemd-hibernate.service.wants
nvidia-resume.service                    | systemd-suspend.service.wants
nvidia-resume.service                    | systemd-suspend-then-hibernate.service.wants
nvidia-suspend.service                   | systemd-suspend.service.wants
p11-kit-server.socket                    | sockets.target.wants
pipewire-pulse.socket                    | sockets.target.wants
pipewire-session-manager.service         | user
pipewire.socket                          | sockets.target.wants
remote-fs.target                         | multi-user.target.wants
systemd-networkd.service                 | multi-user.target.wants
systemd-networkd.socket                  | sockets.target.wants
systemd-networkd-wait-online.service     | network-online.target.wants
systemd-network-generator.service        | sysinit.target.wants
systemd-resolved.service                 | sysinit.target.wants
systemd-timesyncd.service                | sysinit.target.wants
systemd-userdbd.socket                   | sockets.target.wants
wireplumber.service                      | pipewire.service.wants
xdg-user-dirs-update.service             | default.target.wants

seth wrote:

Please post the output of

iw dev wlan0 link # wlan0 speculates on the actual device name

Connected to 02:83:cc:de:e2:97 (on wlan0)
        SSID: CenturyLink1600
        freq: 2412.0
        RX: 5752147 bytes (8302 packets)
        TX: 2115281 bytes (6182 packets)
        signal: -57 dBm
        rx bitrate: 48.7 MBit/s HE-MCS 2 HE-NSS 2 HE-GI 1 HE-DCM 0
        tx bitrate: 137.6 MBit/s HE-MCS 5 HE-NSS 2 HE-GI 0 HE-DCM 0
        bss flags: short-preamble short-slot-time
        dtim period: 2
        beacon int: 100

seth wrote:

Please post the output of
iw dev wlan0 station dump

Station 02:83:cc:de:e2:97 (on wlan0)
        inactive time:  1905 ms
        rx bytes:       5762998
        rx packets:     8348
        tx bytes:       2116825
        tx packets:     6195
        tx retries:     5890
        tx failed:      5
        beacon loss:    0
        rx drop misc:   2
        signal:         -56 [-59, -59] dBm
        signal avg:     -56 [-71, -57] dBm
        tx bitrate:     103.2 MBit/s HE-MCS 4 HE-NSS 2 HE-GI 0 HE-DCM 0
        tx duration:    4727745 us
        rx bitrate:     48.7 MBit/s HE-MCS 2 HE-NSS 2 HE-GI 1 HE-DCM 0
        rx duration:    7541216 us
        last ack signal:-56 dBm
        avg ack signal: -55 dBm
        airtime weight: 256
        authorized:     yes
        authenticated:  yes
        associated:     yes
        preamble:       long
        WMM/WME:        yes
        MFP:            yes
        TDLS peer:      no
        DTIM period:    2
        beacon interval:100
        short preamble: yes
        short slot time:yes
        connected time: 784 seconds
        associated at [boottime]:       11.678s
        associated at:  1755626203934 ms
        current time:   1755626987447 ms

seth · 2025-08-19 19:29:55

No conflicting services and no wonky roaming
But the journal is only ~3 minutes and the average transmission is 100MB, only the reception is ~50MB

Signal isn't "great" but ok, have you tried a 5GHz connection (might be interference w/ your wireless input devices)

Aug 19 10:56:39 mustardpc kernel: mt7921e: unknown parameter 'power_save' ignored
Aug 19 10:56:39 mustardpc kernel: mt7921e 0000:29:00.0: enabling device (0000 -> 0002)
Aug 19 10:56:39 mustardpc kernel: mt7921e 0000:29:00.0: ASIC revision: 79610010
Aug 19 10:56:39 mustardpc kernel: mt7921e 0000:29:00.0: HW/SW Version: 0x8a108a10, Build Time: 20250625153620a
Aug 19 10:56:39 mustardpc kernel: mt7921e 0000:29:00.0: WM Firmware Version: ____010000, Build Time: 20250625153703

"mt7921e.disable_aspm=1"

yawankels · 2025-08-19 19:46:12

I have measured it when it is using both 2.4GHz and 5GHz, the internet speed is equally slow.
But I wonder to myself, when I had windows, did it squeeze a good amount of speed out of a poor signal, or did it not even have a poor signal?

seth · 2025-08-19 20:35:33

Since the journal is only 3 minutes I assume you didn't actually run any speedtest during that time, right?
Disable aspm (the "power_save" parameter you were likely looking for ) run a speed test and post journal and iw station dump after that.
As for the signal quality, can you move closer to the AP?
Are there (lots of) other 2.4GHz devices around?
(5GHz typically stays more clear of that since BT and w/ that all the proprietary slangs used by logitech etc. and DECT phones etcetc. operate in the 2.4GHz band)

yawankels · 2025-08-20 18:09:02

Sorry for the delay, I think the forum went down for a bit. Anyways, after doing some stuff, my internet is fully functional again. I think the kicker was a combination of power saving and interference on 2.4GHz. Like, it was selecting 2.4 based on signal strength and not link speed, and power saving was killing the bandwidth for 5GHz, which apparently made it the same as 2.4's speed, and that really threw me off.
Thank you so much for the help.

Arch Linux

#1 2025-08-19 04:55:46

[SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#2 2025-08-19 08:11:44

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#3 2025-08-19 18:13:25

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#4 2025-08-19 19:29:55

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#5 2025-08-19 19:46:12

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#6 2025-08-19 20:35:33

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

#7 2025-08-20 18:09:02

Re: [SOLVED] Slow wifi on desktop, using iwd and systemd-networkd

Board footer