4 ms·
Ethernet usually requires isolation magnetics and transformers, while WiFi is basically just a wire sticking out of an RFIC.
by eigenloss 7y ago
Ethernet usually requires isolation magnetics and transformers, while WiFi is basically just a wire sticking out of an RFIC.
- pjc50 7y agoIt's not so much that the transformers consume more power than just radiating it into the air, but that Ethernet is not designed with power efficiency as a goal. Ethernet devices that need more power usually get it from PoE instead. Without doing any analysis at all, I suspect the idle behaviour is a big difference; Wifi goes silent if there's no traffic, apart from AP beacons, but Ethernet continuously transmits "fast link pulses" every 16 miliseconds to maintain autonegotiation and detect connection lost.
- KirinDave 7y agoHonestly I dunno why it was the case for me. What I know is that I thought I'd save power pushing pulses over copper rather than using a radio. I didn't. In fact it was consistently about 40% worse than wifi. That might be unique to the RPi hardware I used. It might not. Maybe I should have written that article. :)
- londons_explore 7y agoThe Pi does Ethernet with a seperate and pretty power hungry chip. If the ethernet cable is disconnected, that chip mostly powers down. I think it's a Pi related thing rather than being inherent to Ethernet. In fact, if I were to guess, the energy per bit per meter of ethernet is probably far far lower than WiFi.