I just spent 45+ minutes with the Live Chat but am no closer to getting my plight resolved.

I connected my brand new TL-R605 (which is replacing my old Linksys BEFSR41 10/100Mbps) to my home network fiber connection which should yield about >400Mbps Download... but with the router I'm only realizing 60-90Mbps download.

After connecting my router I updated the firmware to the latest (1.1.1 Build 20210723 Rel.64608), peformed a Factory Reset, and since then have made zero changes/configurations. As far as I know the router is running in standalone mode.

The agent in Live Chat suggest I test the link speed, but we couldn't figure out how to do this on a Mac running Big Sur, which has deprecated the Network Utility app. I provided outputs from 'ifconfig | more' and 'netstat -i' and the agent couldn't find the desired information.

[update] I confirmed the speed should be 1000baseT via 'Network > Thunderbolt Ethernet adapter > Hardware'.

The agent's next suggestion was that I go buy a Cat 6 or Cat 7 cables. I'm currently using Cat 5e and have performed all the tests with swapping out other Cat 5e cables with the same result.

Does anyone have any ideas or suggestions? I'd heard setting up TL-R605 could be a bit of a pain but I didn't expect this .

Any help would be appreciated!

Thanks

Below are the speedtest.net and iperf3 results.

Connected directly to Modem:

Connected through Router

iPerf3 results from client

System specs