Ubuntu 20.04 Network Performance Extremely Slow
I just upgraded from Ubuntu 18.04 to 20.04 on one of the Dell XPS 13 machines, and the network performance is abhorrent. Internet speed is very fast from a google speed test (>300Mb/s for both upload and download).
However, whenever I try to browse a website or even run sudo apt update the connection will often time out. My internet is very fast on all other devices and I really don't know how to debug this problem.
sudo lshw -class network -short && nmcli device status
shows
H/W path Device Class Description
==============================================================
/0/100/1c.6/0 wlp2s0 network Wi-Fi 6 AX200
/3 br-96f5b790e29e network Ethernet interface
/4 br-15e76fb81c05 network Ethernet interface
/5 docker0 network Ethernet interface
DEVICE TYPE STATE CONNECTION
wlp2s0 wifi connected CSA HQ
br-15e76fb81c05 bridge connected br-15e76fb81c05
br-96f5b790e29e bridge connected br-96f5b790e29e
docker0 bridge connected docker0
p2p-dev-wlp2s0 wifi-p2p disconnected --
lo loopback unmanaged --
gpd0 tun unmanaged --
Solution:
It seems like this is a pretty common problem, and one without a definitive cause. For me, it was because Ubuntu resets the TLP configuration, and the power management went back to "on". I disabled Wi-Fi power management directly by editing:
sudo nano /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
Then changed the value from 3 to 2, saved changes and rebooted.
I actually got this solution from Reddit and this worked for my case specifically but it seems like it could be caused by a bunch of other things. Read all the proposed solutions below!
Solution 1:
The top voted answer didn't solve it for me and I got this solution from a different source.
This was because Ubuntu resets the TLP configuration when I upgraded from 18.04 to 20.04, and the power management went back to "on". I disabled wifi power management directly by editing /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf and changed the value from 3 to 2, saved changes and rebooted.
Solution 2:
could be the "backport-iwlwifi-dkms" package
I experienced a better performance without this package, so i suggest to remove it
$ sudo apt remove backport-iwlwifi-dkms
this is a known bug
https://bugs.launchpad.net/ubuntu/+source/backport-iwlwifi-dkms/+bug/1869588
Solution 3:
I was having the same problem with slow wireless internet speed and what worked for me was to follow the steps proposed in the following post:
Very slow internet connection on ubuntu 16.04
Basically, I edited the file /etc/gai.conf as super user:
sudo nano /etc/gai.conf
Then I looked for the line with precedence ::ffff:0:0/96 100 and removed the # character that preceded it. I had to reboot my system for it to take effect. It worked like a charm.
The funny thing is that when I was using Ubuntu 20.04 Beta, this problem did not happen. Later, when I installed the LTS version, I started having this problem.
Solution 4:
Thanks a lot for all information you provided above.
Here I want to tell you about my situation.
I have an XPS-13-9360 (i7-8550U,16G,1T) and manually installed a killer 1650 (aka. intel ax 200). I was facing the same issue, extremely slow wireless connection.
And it seems that the problem has been solved since I installed a linux-5.6.7-generic kernel. (While the last one was 5.4.0-low-latency, I don't know why I installed low latency version, all that I did was do-release-upgrade from Ubuntu 19.10 with 5.3 kernels).
Here I recommend that you install a generic kernel instead of all one (by uname -sr, you can see what kind of kernel you are using), and upgrade to a newer kernel if possible.
BTW, I didn't sacrifice WiFi 6 and it seems OK with Linux 5.6.7
Bests, Leon
Solution 5:
Also updated from Ubuntu 18.04 to 20.04 on a Dell XPS 7390, had the same problem, and the accepted solution worked well for a bit (see comments):
sudo nano /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
I would just add for any other newbies like me that Ctrl + o and then Enter saves the changes made, and Ctrl + x then exits nano mode (https://wiki.gentoo.org/wiki/Nano/Basics_Guide). While here, Ctrl + Alt + t is how you open the terminal where you'd enter all these commands.
My current download speed (compared to a Win10 machine on the same desk) is 87 Kbps (vs. 19Mbps), and upload is 6.7 Mbps (vs. 8.5Mbps).