NETGEAR Orbi 850 Series mesh Ethernet link is limited to 100 Mbps or disconnects

The checks in more detail

and moving the satellite closer or wiring it to the router lifts the cap. A switch between the satellite and the device can limit speed if it is a 100 Mbps model. The Orbi's web page shows the link speed of each port, so check it at orbilogin.com. Test the same cable on another device. Firmware updates have affected speeds on the series, so check for a release. Compare the wired speed with the plan. A device with a slow network card can be the limit.

If a wired device only reaches speeds close to the Orbi's wireless backhaul rate, look at whether the satellite uses a wired backhaul in the app; the status screen says Wired or Wireless for each satellite. Changing a satellite to wired backhaul usually takes a minute once the cable is connected and the router detects it. If the satellite is wired and the speed is still low, check whether the cable runs through a wall plate or a cheap coupler, since those can be Cat 5 or damaged and limit the link;

replace them with a direct cable or a Cat 6 keystone. A cable tester shows whether all eight wires work, which is the usual fault in old wall cabling. Another cause on older homes is cabling routed along a power line or through a wall plate that was installed years ago for phone use, and these may be Cat 3 or Cat 5 with poor terminations; a cable tester or a direct patch cable shows whether the wall wiring is limiting speed. Replace the wiring or use a powerline adapter only as a last resort.