On 22/02/2021 09:14, Brian Gaff (Sofa) wrote:
The whole point though is for that to also be a charger, though I have to
say I'm not greatly impressed with their efficiency.


To support the ATX soft start button and wake-on-LAN features, PCs have
long offered a permanent 5V standby supply.

So this USB powering thing is using something that was already there as
an independent subsystem. This would be as efficient as a typical
plug-in wall adapter (I'd hope).

--
Adrian C