Processor caps at 800Mhz

The following commands are used in the .gif below:

time sudo updatedb # See 8 CPUs run at 3.5 GHz. Then set 800 MHz Below
echo 800000 | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
time sudo updatedb # See 8 CPUs run at 800 Mhz. Then set 3.5 GHz Below
echo 3500000 | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
time sudo updatedb # Time is 3.5 seconds instead of 13.8 seconds

To make a long visual short first find out maximum CPU speed before it is throttled:

rick@alien:~$ cd /sys/devices/system/cpu/cpu0/cpufreq/
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:/sys/devices/system/cpu/cpu0/cpufreq$ grep -r .
energy_performance_available_preferences:default performance balance_performance balance_power power 
scaling_min_freq:800000
scaling_available_governors:performance powersave
scaling_governor:performance
cpuinfo_max_freq:3500000
related_cpus:0
scaling_cur_freq:3218768
scaling_setspeed:<unsupported>
affected_cpus:0
scaling_max_freq:3500000
cpuinfo_transition_latency:0
energy_performance_preference:performance
scaling_driver:intel_pstate
cpuinfo_min_freq:800000

Notice the line: cpuinfo_max_freq:3500000 above. 3,500.000 MHz is my processors max speed. So to restore maximum speed I use:

echo 3500000 | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq

Most people do it one by one and some say it's not possible to do them all at once but I've never had a problem doing all 8 CPUs at once. If you want to do one at a time you can use:

echo 3500000 | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
echo 3500000 | sudo tee /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq
         ( etc., etc., etc. )
echo 3500000 | sudo tee /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq

This will restore your CPUs to maximum speed but we still need to find out what package is setting your CPUs to 800 MHz.

Does it still cap at 800 MHz running only on battery, without the charger? My roommate had a similar problem (on Windows), where connected to the charger the CPU was around 800 MHz and, without it, it ran fine. It was a faulty charger that didn't give the right voltage.

We had this issue at my last job (Windows), every so 6 months or so we'd take all of our laptops down the the air compressor and blow out the fans. The Dell model or the particular Intel CPU we all had seemed to be prone to this. It is caused by overheating. We never could figure out why the throttling got stuck but keeping it clean regularly seemed to prevent it. Once someones laptop started acting up again, we would all go use the compressor knowing they would all start acting up soon.

If cleaning out the fans does not help, make sure the fan is running good and that its not obstructed in any way. It's possible the thermal paste is not doing its job, or the fan/heat sync are not tight with the CPU.