BBB CPU power problem (BogoMIPS only 660.76)

RobertCNelson is right.

You can see the active/current govenor with:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

It will likely return ‘ondemand’, which automaticly tunes the frequency/voltage depending the CPU load.
If you do a ‘cat /proc/cpuinfo’ right after boot (heavy load), you will see that the system runs at 990 BogoMIPS