Good afternoon.
Sometimes I need to use my RB951G-2HnD with the powerbank.
What is more efficient in power consumption - to send 5 GB over Wifi (tx power: 26 dBm; acceptable wifi coverage through 1-2 brick walls) or over 20m twisted pair cable from RB951G-2HnD ?
Thanks for the thoughts and answers in advance.
It depends.
For a one on one connection, wifi might be more power efficient purely on medium level.
OTOH cable will be faster so it might possibly negate that difference, purely looking at the time slot at which the transfer happens.
BUT … that wifi radio also needs power.
So still it depends…
Follow my thoughts for a moment …
If you use that RB951 with all radios off, you can still transfer data via ethernet and it will not consume a lot more energy.
Switch on those radios and power consumption will increase drastically, all the rest remains equal (it needs to take data in via WAN interface, it needs to use part of the CPU to process those packets, it needs to send them out over an interface, doesn’t matter yet which one).
Transfer via radio will also be slower, so added consumption over time.
In the larger scheme, I suppose wired will be the winner logically thinking.
Do the test for both conditions and see where you get 
Make sure to use identical data transfers for both cases.
Thank You, holvoetn.