Another question about slow wifi, v 22.04

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Been running Ubuntu 22.04 server on a used Dell Latitude Laptop for a few months and the wifi speed was decent, initially clocking at 130 - 150 MB download. But last month the download speed downgraded to only 3 mb. I found a solution involving MTU and setting it to 1492 seemed to work for awhile, with download speeds returning to about 130MB. Today, download speed is ranging from 23 MB - 32 MB. MTU is still at 1492. Router is a Google Nest on WPA2. Last speed test about a half hour ago from a Windows 11 device (wifi connected) was 269 mb download. Here are some of the system specs:

description: Notebook
product: Latitude 5490 (0816)
 *-cpu
          description: CPU
          product: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
          vendor: Intel Corp.
          physical id: 50
          bus info: cpu@0
          version: 6.142.10
          slot: U3E1
          size: 3389MHz
          capacity: 3600MHz
          width: 64 bits
          clock: 100MHz
       *-network
            description: Wireless interface
            product: Wireless 8265 / 8275
            vendor: Intel Corporation
            physical id: 0
            bus info: pci@0000:02:00.0
            logical name: wlp2s0
            version: 78
            serial: 20:79:18:3b:3b:b1
            width: 64 bits
            clock: 33MHz
            capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
            configuration: broadcast=yes driver=iwlwifi driverversion=5.15.0-60-generic firmware=36.ca7b901d.0 8265-36.ucode ip=192.168.86.60 latency=0 link=yes multicast=yes wireless=IEEE 802.11
iwlist wlp2s0 freq
wlp2s0    32 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 12 : 2.467 GHz
          Channel 13 : 2.472 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Channel 100 : 5.5 GHz
          Channel 104 : 5.52 GHz
          Channel 108 : 5.54 GHz
          Channel 112 : 5.56 GHz
          Channel 116 : 5.58 GHz
          Channel 120 : 5.6 GHz
          Channel 124 : 5.62 GHz
          Channel 128 : 5.64 GHz
          Channel 132 : 5.66 GHz
          Channel 136 : 5.68 GHz
          Channel 140 : 5.7 GHz
          Current Frequency:2.462 GHz (Channel 11)

From the nmcli device show command

GENERAL.DEVICE:                         wlp2s0
GENERAL.TYPE:                           wifi
GENERAL.HWADDR:                         20:79:18:3B:3B:B1
GENERAL.MTU:                            1492
GENERAL.STATE:                          10 (unmanaged)
GENERAL.CONNECTION:                     --
GENERAL.CON-PATH:                       --

Device hasn't been restarted since the MTU update (from 1500 to 1492). I'd prefer not to interrupt some tasks on the server, but if you think a restart is worth a try, I can give that a shot.

you have a lot of avaliable channels but is any of them free from traffic? — trond hansen, Apr 13 '23 at 03:39
Channel 11, to which you are connected, is a 2.4 gHz channel. Aren't you able to connect to the much faster 5 gHz channels? Is your Google Nest set to autoselect (incorrectly) the 2.4 gHz segment? My Intel 8265, connected to channel 149, gets download speeds > 400 Mbps. — chili555, Apr 13 '23 at 14:09

score 0 · Answer 1 · answered Apr 14 '23 at 00:58

Thanks trond hansen and chili555. I ended up running this sudo iwconfig wlp2s0 channel 36 . I couldn't get the frequency from the Google Nest, so guessed at the lowest 5 ghz frequency. Last three speed tests have ranged between 162 mb and 201 mb download.

Another question about slow wifi, v 22.04

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