I've got a Cubox-i 4 running Armbian stretch 4.16.8 and I noticed that the frequency never seemed to drop below 996MHz (even when on zero load) using sudo cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq whereas armbianmonitor -m showed the same, occasionally showing 792MHz.
Looking at Orange Pi Zero I managed to see what the issue might be.
Changing /etc/default/cpufrequtils to "powersave" dropped the frequency to 396MHz but stayed there even when under stress (stress -c 4 -t 60). Changing the value to "conservative" gave me what I wanted. 396MHz with no load, rising to 996MHz when under load.
Hopefully others might find this useful.
Using lsmod - shows only 3 modules:
cpufreq_powersave 16384 0
cpufreq_conservative 16384 1
cpufreq_userspace 16384 0
So the default setting "ondemand" isn't doing anything.