Measure Raspberry Pi Undervoltage + True Clock Speeds

I uploaded a quick gist that will measure your Raspberry Pi’s true clock speeds using the vcgencmd. Don’t believe what other tools like cpufreq tell you that your Raspberry Pi is running at because they are lying to you!  Raspberry Pi Undervoltage is also a very big issue and this script will detect it and notify you.  The true clock speeds are controlled by the firmware.  The vcgencmd is the official way to interact with the Raspberry Pi’s firmware and are the only readings you can really trust!  Available at or click read more to view it directly.

When I wrote this script I noticed when I was trying to overclock using cpufreq-utils it was reporting totally different numbers than what vcgencmd was giving me. That’s when I did some research and learned that the true speeds are controlled by the firmware. That is why the best way to overclock your Pi is definitely by using /boot/config.txt and putting the parameters there.

I also learned writing this that my Raspberry Pi Undervoltage had been triggered even though it was connected to a powered USB hub and bought a better power supply. The cheap Canakit Raspberry Pi power supply on Amazon is the one I chose.

Stay tuned for an upcoming article I’m working on detailing my journeys with overclocking the Raspberry Pi / Pi2 / Pi3!

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