Arduino to breadboard - 3.3V power supply?

Hello,
Looking on the internet I was not able to find answer to this...
I have followed this tutorial to have a standalone arduino on breadboard: Arduino - Home.
Currently I use, as power supply, my Arduino UNO connecting directly the 5V and GND to the breadboard + and - (ignoring the 5V regulator on the tutorial).

I'm wondering if I can power supply the breadboard using 3.3V instead. Are there any side effects, or it is going to work?
I think that doing this also the serial connection and outputs will work at 3.3V, is it correct? Can I than connect it to another device with 3.3V serial interface?

Thank you,
dk

there is a voltage vs speed chart in the datasheet, in a nutshell at 3.3v the best option for using arduino means cutting the clock back to 8Mhz

If the Arduino is at 5V and breadboard at 3.3 you probably will need level shifters for the signals - 3.3V devices wont tolerate 5V and no device should have a logic input outside its supply range.

The ATmega chips will usually work at 16MHz at 3.3V at 25C, but you have no guarantee

d82k:
I'm wondering if I can power supply the breadboard using 3.3V instead. Are there any side effects, or it is going to work?
I think that doing this also the serial connection and outputs will work at 3.3V, is it correct? Can I than connect it to another device with 3.3V serial interface?

It will work, but not at 16MHz. The datasheet has a graph of maximum clock speed vs. voltage.

Thank you all for your answers.

I have read a bit on the internet, and, if I have well understood, I can use the seme circuit of the tutorial just substituting the crystal 16mhz with one at 8 and the circuit should be good. Any other change to the capacitor or other components is needed?

Than I should change the bootloader using the one "Arduino Pro or Pro Mini (3.3V 8MHz) with atmega328" and my arduino on the breadboard should work at 3.3v right?

Thank you,
dk

d82k:
Thank you all for your answers.

I have read a bit on the internet, and, if I have well understood, I can use the seme circuit of the tutorial just substituting the crystal 16mhz with one at 8 and the circuit should be good. Any other change to the capacitor or other components is needed?

Than I should change the bootloader using the one "Arduino Pro or Pro Mini (3.3V 8MHz) with atmega328" and my arduino on the breadboard should work at 3.3v right?

Right.