When running the board at room temperature (20 C) without any extra cooling mechanisms added, how much can the Arduino Uno be overclocked?

Also, what would I need to change/update to overclock the board?

  • Do you want to be able to program your Arduino once it has been overclocked? In that case the answer is probably 0%.
    – jippie
    Mar 7, 2014 at 7:50
  • You probably get a higher and more reliable performance improvement by reviewing your code and ditching some standard Arduino libraries.
    – jippie
    Mar 7, 2014 at 17:43
  • See the following question
    – mpflaga
    Mar 7, 2014 at 23:14

1 Answer 1


With no active cooling, most ATmega328P will run at 30MHz but you will need to up the supply voltage to ~6V. I have never done this on an Arduino board, just an ATmega328P.

I provided an external clock from a signal generator.

The only way to achieve a speed faster than 16MHz is to change the crystal/oscillator/clock input for one faster than 16MHz.

As this was just an experiment, I didn't alter f_cpu in boards.txt, so all timers etc. would be incorrect. Baud rates would also be incorrect - the only way to upload code was to change back to 16MHz.

  • 1
    Very interesting data about the actual clock rate supported. As for the only way to upload code, maybe it would be easier to use ISP instead of a serial boot loader in such a setup? Mar 8, 2014 at 23:01

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