Internet is very slow, Windows 10?

I bought and installed Windows 10, my notebook is a few years old, but well equipped,

i7, 8G RAM, 64Bit, 256SSD, etc,

A few days after the installation of Win 10, the internet was very slow, something I have never had with Win 7. I reinstalled Windows, no improvement, I totally reduced the protection and disabled the pop-blocker, but no improvement.

do you have ideas why it can be?

Go on speedtest.net and look what's there, then call your provider and complain

I tested the net on my phone and my iPad, it works normally