The Arduino (Mini) Board (ATmega328P) runs with 5V at 16 MHz with a RC oscillator.
Incorrect. A resonator is used, which is not the same at as an RC oscillator.
Do you have a programmer? It's simple enough to change the fuses in boards.txt to enable the divide by 8 circuit to run at 2 MHz and see how things look.
Change the speed there to 2000000UL as well.