At least that’s the theory but since it’s always stupid to blindly believe into the numbers thrown out by some piece of hardware + some software let’s check…
The generated values with this 172.5 divider look like this:
(Most right columns are input voltage by SARADC postprocessed with formula and overall consumption measured with a NetIO powermeter at wall)
root@rock-5b:/home/tk# sbc-bench.sh -m
...
Time big.LITTLE load %cpu %sys %usr %nice %io %irq Temp DC(V) mW
15:16:28: 600/1800MHz 0.20 1% 0% 0% 0% 0% 0% 46.2°C 5.06 4910
15:16:49: 600/1800MHz 2.05 99% 0% 98% 0% 0% 0% 54.5°C 5.08 6120
15:17:09: 600/1800MHz 4.30 100% 0% 98% 0% 0% 0% 56.4°C 5.23 7810
15:17:29: 600/1800MHz 5.42 99% 0% 98% 0% 0% 0% 57.3°C 4.97 8440
15:17:50: 816/1800MHz 6.15 100% 0% 99% 0% 0% 0% 59.2°C 5.13 8520
15:18:10: 1008/1800MHz 6.68 100% 0% 99% 0% 0% 0% 60.1°C 4.96 8710
15:18:30: 1200/1800MHz 7.20 100% 0% 99% 0% 0% 0% 61.9°C 4.99 9020
15:18:51: 1416/1800MHz 7.43 100% 0% 99% 0% 0% 0% 62.8°C 5.05 9320
15:19:11: 1416/1800MHz 7.67 100% 0% 99% 0% 0% 0% 64.7°C 5.08 9610
15:19:31: 1608/1800MHz 7.77 100% 0% 99% 0% 0% 0% 65.6°C 5.17 9820
15:19:52: 1608/1800MHz 7.83 100% 0% 99% 0% 0% 0% 67.5°C 5.03 10060
15:20:12: 1800/1800MHz 7.95 99% 0% 99% 0% 0% 0% 70.2°C 5.03 10660
15:20:32: 2016/1800MHz 7.96 100% 0% 99% 0% 0% 0% 73.0°C 5.05 11390
15:20:52: 2016/1800MHz 7.97 100% 0% 99% 0% 0% 0% 74.8°C 4.91 12150
15:21:12: 2016/1800MHz 7.98 100% 0% 99% 0% 0% 0% 76.7°C 4.86 12740
15:21:33: 2208/1800MHz 8.31 100% 0% 99% 0% 0% 0% 80.4°C 5.17 14440
This is Rock 5B powered by a dumb 10W USB-A power brick with an USB-A-to-USB-C cable connected. This power brick is know to drop below 5V already at 9W or 10W wattage. And this in a pretty linear way.
As load generator I used stress-ng --matrix 0 in another terminal and allowed the A76 cluster to constantly increase clockspeed and as such overall consumption. At 2.2 GHz and over 14W the board froze then. But the SARADC readings postprocessed with ‘our’ formula look both too high and too erratic.