dsese1234:
Hi Thanks for quick response. so is there other way to speed the clock speed of atmega328?
Running a 328p chip at greater then 20MHz via an external crystal resonator or an external crystal oscillator is called 'overclocking'. Some people have experimented with doing that and maybe reached 30Mhz or maybe a little higher, I forget the speed they got to, but it's certainly not a recommended practice to run faster then ATMEL ratings and the chip will run hotter and may need some kind of cooling to prevent chip damage when playing with 'overclocking'.
Lefty