Download speed 4 times as bad as normal?

For a few days / weeks I have had the problem that instead of downloading at 5mb / s as before, I only download at a maximum speed of 1.2mb / s.

On other devices like the Xbox everything works exactly as it used to, which is why I suspect it is due to my PC.

Information about my connection: I'm using a Killernet E2400 Gigabit Ethernet controller.

I've tried different things like:

-Router restarted

-Searched for new drivers for my ethernet connection

-IPv6 protocol disabled

-Unnecessary processes deactivated in the background

-Windows autotuning disabled

If you have any ideas or have ever had such a problem yourself, I would be happy to receive suggestions

That can apparently Wi-Fi and lan.

What is it with you have you connected the PC via LAN cable or via WLAN?

Have you tried another browser?

Via LAN cable

Yes is equally bad everywhere

Uninstall and reinstall all LAN drivers.

You should of course download the new LAN drivers beforehand.

If you have it can also be an advantage if you use the old drivers, e.g. Install from CD. Sometimes manufacturers make mistakes with a driver update and then you have the salad.