@Kevin_Z  Could you please explain same steps but for old interface? I have Archer C5 V1 (green UI).

Firmware version:0.9.1 3.0 v0045.0 Build 160411 Rel.42416n

Hardware version:Archer C50 v1 00000002

 

I also have same mysterious problem. Mac plugged directly  in to ethernet socket gives 1000Mps (using either of 2 cables). Then use same 2 cables for Mac to router, then router to wall socket = 100Mps. How can I enable max speed for ethernet and wifi please?

I have - but please can you help with instructions for older UI? You suggest "Go to Advanced-system tools-system parameters to edit the duplex, change it to 1000Mbps full-duplex if you have a gigabit line, then reboot the router." The menu is different for C5 v1

@Kevin_Z  so sorry, it is AC1200 Archer C50 V1 as in the pasted text:

Firmware version:0.9.1 3.0 v0045.0 Build 160411 Rel.42416n

Hardware version:Archer C50 v1 00000002

Where can I get support for this problem on this model please? It is not a cable or PC issue.

 

It has the older UI, green not blue:

yes I ran a speedtest, 1) with laptop via ethernet into wall socket 2) with same laptop and cable via TP Link also via wifi give same speed (80-90Mbs)

I much appreaciate your answer!, after hours fighting with my ISP provider, thanks to your answer, i was able to configure the negotiated speed on my AC2300 this solved the dropped speed on my TPLink. i have months paying a 100mbps and only getting 50-60mpbs on my wifi. thank you so much, now i can enjoy the speed im paying for!

@Emiley1337 

 

wanted to share my experience, maybe it will help somebody.

Bought today Archer AX50 mainly because I wanted to have stronger Wired LAN connection. I got new internet where speed increased to 1Gbit. Previous router was able to support max 100MBit and that was the main reason why I bought stronger router with 1Gbit LAN connectors. 

 

When I connected router I was getting 200-300Mbit on a wired LAN. Wireless was just okay, on an iphone 11 around 650Mbit was constantly available so the problem was wired connection. When I connect computer directly to modem, I am getting 800-900Mbit so obviously to me problem was router. 

 

I have tried exchanging cables like few people mentioned, but makes no sense that same cable is getting thru one device 200-300Mbit and on another 800-900Mbit. So it wasn't the cable that was the problem. 

I have upgraded the firmware also on the router, didn't help much. 

 

I was frustrated and decided to exchange it for something else, because obviously the problem was only wired LAN. 

 

As the last resort I have tried updating the drivers of the wireless card. BINGO. When actually downgraded to a driver from 2016 (Realtek 1gbit ethernet connection), I was getting constantly 800-900Mbit.  

 

It makes no sense to me why the ethernet card, even downgraded driver was the problem, when the same card was working without the Archer. So playing with the drivers of the ethernet card helped me (restoring to the driver actually from 2016). Saw that with this router even older driver is better. My results: 

driver

28.8.2018 latency 11ms UP 840Mbit DOWN 96MBit

14.7.2016 latency 5ms UP 868Mbit DOWN 98MBit constantly this driver was giving me best numbers

23.3.2017 latency 9ms UP 771bit DOWN 92MBit

15.6.2018 latency 9ms UP 846Mbit DOWN 97MBit

1.10.2021 latency 12ms UP 876Mbit DOWN 98MBit