You cannot overclock an i3 3220. If you want to overclock, you need to step up to an i5, preferably an unlocked k edition one. The non k edition chips have some capability since they have turbo capability that the i3's lack.
which software shold be used to overclock i3 3220 without any harm?
core i3 3220 cpu cannot be overclocked as it has neither turbo nor unlocked turbo multiplier. you may be able to overclock the 3220 by overclocking your bclk by a few mhz and gain 100 mhz (more or less) on a z77 motherboard. not worth the effort.
You can't overclock a non-k cpu (you could by changing the base clock but it's dangerous for data corruption even at 101 over 100 and the fastest base clock i've seen is 105 so it'll only bring you to 3.465ghz over the 3.3ghz stock (you'll never notice it and you compromise the stability and the long term usage by doing this...)