Comment by 0xbadcafebee
8 hours ago
The author's chart is incorrect. He has the idle power at "1" for the Pi 2, "2" for the Pi 1/3/4, and "3" for the Pi 5. No other published power draw numbers are whole numbers like this, they are floating points, like 1.2, 1.9, etc. Google around and you'll find several different power testing comparisons with more detail.
Most reports show the Pi 4 drawing ~2.8 W in idle headless mode, and the Pi 3B+ drawing ~1.9-2.0 W in idle headless mode. With full load the Pi 4 draws more (6.4W, to the Pi 3B+'s 5.1W) with the same test procedure.
But you do have to check the testing method; enabling/disabling hardware features changes the figure, and each additional USB peripheral draws more power. Otoh, to get a "max power draw" reading you have to enable everything and stress all CPUs at once, and then it will dip under thermal load.
I had Home Assistant on an RPi 3 with 1 GB RAM and a USB thumb drive until sometime maybe 7-10 days ago when I switched to an RPi 5 with 8 GB RAM and the 256 GB SSD and NVME had sold by the RPi company.
The 3 was and the 5 is plugged into an energy monitoring smart outlet. Here's a graph of power for that outlet [1] for the last 30 days.
HA uses long term statistics for older than 10 days, which is why the 2/3 to the left shows much less variation. The switch from the 3 to the 5 is somewhere a little way into the right 1/3, where it is using shorter term data which has a much higher sample rate.
It does look like the average power goes up with the 5, but not nearly as much as I would have thought. The left 2/3 which was definitely all RPi 3, averages 2.48 W. From Jan 17 to the present, which was definitely all RPi 5, it averages 2.64 W.
If those reports of 2.8 W for an idle 4 are accurate I'm curious why my HA 5 is lower. I've got an unused energy monitoring smart plug of the same kind my HA Pi is on. I'll have to put the 4 on that and see how it compares.
[1] https://imgur.com/a/qa7SD2O