I have VDSL2 Internet in Germany via Vodafone (ISP Vodafone/Arcor_VDSL(über Telekom)) and the Archer VR600v seems to have some problems processing it. The speed is fluctuating a lot:

The minima are around 20 MBit/s, sometimes down to 5 Mbit/s which causes problems in video calls and video streaming.

My old AVM Fritzbox 7360 doesn't have any problems and has the average (Durchschnitt) download speed > 50 Mbit/s constantly.

The problem is same for LAN and Wireless connection.

When I do a factory reset, the speed is fine for couple of days and then the problem occurs again. After a normal restart, the problem doesn't fix itself.

Before, I had VDSL2 from Deutsche Telekom (same infrastructure and cables) without any problems.

Any idea what could cause the problem? Answers in English or German are very appreciated.

Thanks a lot