Network speeds differ according to boot source

[stevef]

Would be interesting to know if youtube videos played as expected before VirtualBox was introduced to the installed system.

Any idea what the tunnel is for ? I guessed at VPN, but is it related to virtual machine ?

Edit to request clarification.
In your original post

I tried another Llinux version to test this (MX) and the results are the same.

I initially read this to mean that MX had the same symptoms - i.e. ok on live, not ok after installation, but it could be read as no difference between installed and live versions of MX.  Can you confirm which you meant please ?