The standby power consumption for my desktop systems is typically 3 or 4W, which is reduced by only 1W when I switch them off. In other words, they need to be disconnected from the mains power when they are off to be the brightest shade of green.
Very impressive - does that mean your system uses only 1W in idle, the rest is the PSU? I checked the PC's in my house, one of them was 19 Watts when off! The best was only 5 Watts.
First off, I donâ€™t know how accurate my power meter is when working with such small wattages, so thereâ€™s potentially a lot of room for error here.
When a PC is switched off but still connected to the mains power, it still consumes energy, most of which is possibly consumed by the power supply as you suggested.
The extra 1W is the difference between standby and off and nothing to do with idle. The only way to get to 0 watts is to disconnect the PC from the mains power.
Iâ€™ve noticed that even my PicoPSU/Core Solo system which consumes 20W at idle, still consumes 3-4W on standby.
My Core Duo laptop registers 0 Watts on standby though and my TV 1W, so maybe the power meter is up to the job.
This 3 or 4W on standby/off is not insignificant, as if my low power desktop is on 4 hours a day and off or on standby the other 20 hours, its daily power consumption is:
4 * 20 = 80 +
20 * 4 = 80
Half the daily power consumption is from when the PC is not even on.
I have a 20â€