I've found that several of my internet-dependent devices can connect via ethernet and wi-fi at the same time. So, is that a good/bad idea? Or, should I choose one over the other and is a hard-wired connection always better than a wi-fi connection?

Thanks.

Connecting the same device via both WiFi and ethernet is not advisable. You can create a lot of interesting, not mention difficult to troubleshoot, network conflicts that way. But there is no conflict if some devices are WiFi only and others ethernet only. I have a variety of both on my LAN.

Wifi is convenient because the devices are not "tethered" to an expensive ethernet cable but ethernet is easily faster, more reliable, and because of its greater bandwidth less affected by traffic load. If it weren't for the effort and cost of running ethernet cable all of my desktop computers and devices would be connected via ethernet. Just remember, your internet speed is limited to what your ISP provides which is almost certainly slower than either WiFi or Ethernet.

Thanks. Makes sense.

I've got my router in the back room – my laptop, cell phone, entertainment center in the front room. I have a Devolo mesh extender to get the signal from one room to the other.

Still trying to figure out which solution offers the best signal. Netflix started buffering last night, even though it was connected via ethernet. I'll try wi-fi tonight.

That was not your LAN (local area network) it was your WAN (wide area network). Even the slowest ethernet is far faster than what is needed for streaming Netflix. I would bet money your ISP's network was overloaded and running slow.

The problematic ethernet connection comes at the end of a powerline extender. Does that make a difference?

Watching Netflix via the wi-fi (only) connection was faultless last night.

I've found a way to test connection speed via the Netflix app, but it give wildly varying results.

A Roku streaming stick gives much better results from the same wi-fi source. Go figure...

Ethernet via Powerline has two different vectors for failure.....the physical interface and the electronic.

In a conventional ethernet network, the data streams are carried by a straight-forward path....the CAT 5 or CAT 6 ethernet cable. If the cable is well made, with proper connectors at each end, then the data path is normally not a contributing factor to variations in throughput.

With Powerline adapters at each end of the data path, we have introduced both an electronic variable in the adapter itself and a physical factor with the house wiring being used to complete the data path between Powerline adapters.

I would say that your observed throughput loss over ethernet can be directly tied to the Powerline adapters and house wiring.

Thanks. I'm inclined to lay the blame on the house wiring.

After all the chopping and changing, my TV Netflix wi-fi connection seems to have stabilized to near the same figure as the Roku streaming stick. So, the Devolo mesh wi-fi seems to be doing its job.

(I have Covid-19 to thank for my new 48" OLED tv and 4K blu-ray player. Loads of time for indoor pursuits and the inability to spend money on outdoor pursuits.)