Increasing Arduino Mega MHz Frequency?

Hi all, could anyone tell me if it is possible to increase the processing speed of my Arduino Mega? If yes, can anyone tell me how and by how much? I want it to run fast and reliably. I'm thinking about doing it for fun. Thanks.

The ATmega2560 on the Mega is only rated to run at a maximum speed of 16 MHz, which is what it's already at. While it's possible to overclock, operating outside the limits specified in the datasheet could result in unstable operation and thus would not meet your requirement of reliability.

Likely there is much more room for improvement by optimizing your code.

If you finally do find a need for more speed then of course you can accomplish this by switching to a more modern microcontroller. The Arduino Due has the Mega form factor but with a much faster processor. Other popular options are the SAMD boards such as the Zero, Teensy, ESP8266, ESP32, STM32.

Hmmm... Thanks pert, for specifying if it is possible. Is it possible with Due's, Uno's and more? How?

You might be wondering why I need such fast processing speeds, but the answer is I don't. I am just curious if it is possible and I do have some extra boards laying around that I want to try it with.

I'm thinking about doing it for fun.

So go and buy a few different crystals and replace the one that's on the board. At least you will learn how to desolder a surface-mount part pretty well.

Once you do that, you need to change the baud rate used to upload the code. If you don't get this right then you can't upload any new code. There's only one clock on an Arduino so unlike overclocking the core of a PC, any small change will change everything.

There is a 20 MHz ATmega2560 board configuration in MegaCore that will make the software side of things easy if you decide to have a go at overclocking:

Is it possible with Due's

The Due is already running at 84 MHz. Of course clock speed is not going to be an absolute indicator of processing speed when you change architectures but certainly it's going to be faster than a Mega. It looks like it should be possible to increase the clock speed of the Due but you'd need to do some research on that (probably starting with the datasheet). I have no experience with Due.


The ATmega328P on the Uno is rated up to 20 MHz. To run it at 20 MHz you need to:

  • Replace the 16 MHz oscillator on the Uno with a 20 MHz oscillator.
  • Install MiniCore:
  • Select Tools > Board > ATmega328
  • Select Tools > Variant > 328P / 328PA
  • Select Tools > Clock > 20 MHz external
  • Connect an ISP programmer to the ICSP header on the Uno. If you don't own a dedicated ISP programmer you can use a spare Arduino board as an "Arduino as ISP".
  • Tools > Programmer > select the appropriate programmer
  • Tools > Burn Bootloader

I know that overclocking of the Uno/ATmega328P beyond the rated 20 MHz has been done, more just for fun than for practical reasons. You can find some YouTube videos and other documentation of this where people are using various techniques for cooling the microcontroller at unreasonably high speeds.

If you want to use exotic clock speeds on the UNO, you can follow this guide: