I've seen many posts regarding this Archer c6 problem but none of them have a proper solution for it.
The problem is pretty much the same: the LAN ports are capped at 100 Mbit/s while the actual speed should be 400 Mbit/s.
Archer c6 is connected to the Vodafone router (model: Arris TG3442DE) which also has 4 Gbit LAN ports, and the Arris router is connected to an internet line.
When my laptop is connected with the cable (CAT 6) to the Arris router LAN port, the speed is around 370Mbit/s (which is accurate), but when I connect the laptop to the Archer c6 LAN port with the same (CAT 6) cable, it only shows 95-97 Mbit/s, no matter how many times I measure.
I tried this with both mods on Archer C6: access point, and router - the result is the same.
I also tried the instructions that were provided in the previous threads: in the router system settings the duplex is set to 1gbps; in my network adapter settings the duplex is set to full 1gbps; my network adapter is Realtek PCIe GbE Family Controller.
Attaching the screenshots as well. The laptop is connected to LAN port 3, it shows a 1Gbit full duplex, LAN ports 1 and 2 are offline (screenshot 1).
Thank you in advance for any solutions.