wifi speed very different between 16.04 lts and other o.s. ?

[Coeur-Noir]

Hi,
here is one machine with 4 installed o.s. :

• ubuntu 16.04 ( unity ) lts
• KDE-Neon ( so also 16.04 )
• Ubuntu-Budgie 18.04
• Ubuntu ( default DE ) 18.04

On the first my internet speed through wifi is about 16Mo/s which is very comfortable.
On the 3 others, that speed never goes beyond 6-7 Mo/s and is most of the time much slower
( it's been more than a week I test many times a day ).

I followed same method on each system for installing 8723bu. Same files were modified ( /etc/modules & /etc/modprobe.d/blacklist.conf ) lsmod confirms everywhere 8723bu is in use and all systems have the same Linux kernel.

How / where can I compare the difference between installation, regarding the driver specifically maybe ?
Maybe the version installed on 16.04 ( where it works ok ) is older / newer ?

( for reference : https://forum.ubuntu-fr.org/viewtopic.php?pid=21945758#p21945758 )

[jeremyb31]

For Ubuntu, in terminal do sudo sed -i 's/3/2/' /etc/NetworkManager/conf.d/*
Reboot