Update: This works on 3.8.x kernels too. I used MIN_SPEED and MAX_SPEED of 1704000 instead.
For the 3.8.x kernels —
CPU speed file:
sudo apt-get install cpufrequtils
Create a file: /etc/default/cpufrequtils with these contents:
ENABLE="true" GOVERNOR="performance" MAX_SPEED=1700000 MIN_SPEED=1700000
Note:If your CPU temperature hits 85C, this will be overridden to force it down to 800Mhz. Check with this script:
while true do sleep .5 cpufreq-info |grep "current CPU" sudo cat /sys/devices/platform/tmu/temperature done