I have two hard drives in my machine, one boots Windows 10 and one boots Arch Linux. I have a new(ish) Wifi network card plugged into the back of my machine since moving to a new flat. The Windows boot manages to connect and get slow but stable speeds around 15MB/s on repeated speedtest.net runs. The linux boot however can get similar speeds, typically for the first minute or so of the boot, and then drop off completely.

The card might not be the best, and I could look into a different solution, but I should be able to attain similar speeds to the Windows boot.

I confess that I have tried a few different methods to connect to Wifi, including wifi-menu, iwd, netctl, and now currently using NetworkManager which I think was installed all along. I have tried my best to remove and disable all processes related to these older attempts but perhaps something remains.

Can anyone point me to perhaps some log file which might explain why this connection drops?

Dear Somelinuxuser,
network manager saves the log under syslog
in /var/log/syslog in a debian based linux distribution
dmesg also can help you
if you start network manager in a terminal you would be able to see the log afterwards
If you need further help, let me know
Regards,
T

New(ish) wifi cards are frequently more problematic on linux than on windows. Google your specific card or chipset can probably find a few posts from others with similar issues & suggested solutions. It is possible that there is a proprietary driver posted on github or something that will work better than the one in kernel, and it is possible that there is a solution for the in kernel driver posted as well. It's also possible that until further driver development evolves your linux driver's performance will be poor.