Ethernet to google fiber speeds drop, then return with cable unplug MacBook Pro

thanks for your reply

it's the google fiber supplied router that was checked out by a technician who came by

usually top speeds are 800-900 mbps or so but then it drops to around 90mbps

the connection is rated at 1000 google fiber but it's supposedly normal to max at about 800-900

I'm using a belkin ethernet adaptor sold by the apple store, but I am skeptical this is the problem because I have tried three other adaptors and the same problem remained.

Keep in mind the most curious element here is that if I unplug the cable and plug it back in I get higher speeds right away.

Thanks, there is only Standard 1500 and custom, no "flow control" under full duplex, see image

thanks for your help --

thank you - I have made the changes to the settings you indicate but the speeds are still less than 100mbps, then I unplug and replug and they go up to 800mbps.

this is very strange.

I'd suspect it's the adaptors but I have swapped out 3 for comparison.

I also suspected that it was some kind of weird cable heating issue, but the speeds go down even when the comp hasn't been used. So there's no correlation with intense accessing or duration of access and the speeds going down.

Is it possible that google fiber is doing some kind of throttling that gets reset when I unplug and plug back in?