Default prescaler of Arduino DUE

Hi. Just like the title, What is the default prescaler of Arduino DUE? And how to set it? Thank you!

Which prescaler are you talking about ?

Which prescaler are you talking about ?

I dont know exactly what is it called in English. In this case, I want to use full of 84MHz CPU speed of the ATSAM3X to have the board execute the commands, tasks as fast as possible.

The default CPU clock is 84 MHz. I am not sure to understand your question, perhaps you should restate your question.

Post your code ( between code tags) if you have any issue relative to its execution speed.

An extensive use of PDC and AHB DMA is a consistent method to speed up a code, but generally speaking, the quality of code writing is the most important factor.

The CPU speed when running the arduino core is 84Mhz.
If you were to run non arduino code, the default will be a 4Mhz internal RC clock.