Hi All,

I bought an Archer C6 AC1200 from a renowned retail store in Malta as it advertised 1GBps support. From the ISP modem I get an output of 1Gbps as my ISP package provided me with a max speed of 250Mbps and wanted to extend this speed to the back-end side of the apartment.

When I connect the CAT6 ethernet cable going from my ISP router directly to my PC, I see the ISP advertised speed, 250MBps. When I connect it to the WAN port on the AC1200 C6 and the cable provided (also tried another cable) to a LAN port going to my PC, I only see 95-99MBps.

Unfortunately the router seems to be limited to a max of 100mbps as the max speed I'm seeing is around 90-95mbps on both ethernet and wifi. This was confirmed by checking the negotiation type on the WAN port, which is 100MBps full duplex.

I've tried setting the router on both access point and router modes, no difference between the two in speed received.

I've also tried adjusting the QoS to a max of 1000mbps, no change.

I've also tried the instructions provided by TP-Link personnel provided in this thread as i saw that the negotiation was set at 100mbps: 

https://community.tp-link.com/en/home/forum/topic/192286

- changed the duplex setting to 1000mbps but to no avail. The speed remained limited to 90-95mbps, even though negotiation is set to 1000MBps.

The irony is that I took the router to the Maltese retail store and with a few tweaks and on wifi they got 400mbps plus. I plugged it again at home, didn't change any of their settings and I got 90-95mbps.

I want to single out every possible troubleshooting point and I believe I have exhausted my options here. I strongly believe there is something wrong with the WAN port, as LAN ports are showing 1000Mbps full duplex negotiation when connecting my PC.

Don't know what else I can do to remove this bottleneck. Would greatly appreciate assistance in this regard.  

Thanks and kind regards,

Mark