The system in intentionally undervolted a bit due to all the shared components. Running them all at 1.3V would increase power consumption.
The following shows the actual measured voltages following a 30 minute stress test at -40C and +85C
== Set speed and test voltages @ -40C
root@arago:~# echo 456000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
root@arago:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
456000
root@arago:~# cat /sys/class/regulator/regulator.5/microvolts
1275000
root@arago:~# cat /sys/class/regulator/regulator.3/microvolts
1275000
root@arago:~# stress --cpu 2 --io 1 --vm 1 --vm-bytes 5M --timeout 1800s --verbose > output-40C
Measured voltages: 1.271,1.277
== Set speed and test voltages @ 85C
root@arago:~# echo 456000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
root@arago:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
456000
root@arago:~# cat /sys/class/regulator/regulator.5/microvolts
1275000
root@arago:~# cat /sys/class/regulator/regulator.3/microvolts
1275000
root@arago:~# stress --cpu 2 --io 1 --vm 1 --vm-bytes 5M --timeout 1800s --verbose > output85C
Measured voltages:1.271, 1.279