I have TP Link WPA-4420 (300Mbps) powerline extender to extend my network to the basement of my home.
There are no network cables there.
I just updated my Internet connection to fiber optics. If I connect my laptop straight to my router,
speedtest gives me 40/5mbps (down/upload)
When I run the speedtest from the basement I have 10/1 mbps at the most.
I just made a firmware update to TP Link, but there is no difference.
My router is Vodafone H 300s