Pentium g620

You have been told correctly; the CPU is locked; not overclockable. Same with integrated graphics.

I wouldn't say that it cant be overclocked but it's ability is extremely limited to only the base clock depending on the board. If the option to adjust the base clock is available you can raise that base clock from 100mhz to 105mhz usually but beyond that the system becomes a lot less stable.

^^ +1

It can, but very, very limited ability. If it had overclocking ability like the i3 5xx's this thing would have been a beast.

can i know why this processor cannot be overclocked?why intel locked that ability?if this cpu can be overclocked,i am sure that
it can surpass the ability of i3 processor....

Because instead of using separate PLL/clocks for each bus in the system, Intel used only one. While you raise the speed of the BLK, you raise the speed of the PCIe and PCI buses as well. These devices don't tolerate higher speeds which is what prevents the BLK from being raised to what it used to be able to do.

i see..is there any ways to increase this processor performance like we used to do in the bios like increasing the FSB for the other processor?is there any other ways to do it on intel g620?

^^ No. Intel has done it themselves. That's why you get the G630, G840, G850 and G860 at the same time.

but,i am asking for your wise opinions..what do you think about this intel g620?is it good or not?for gaming purposes?

its not bad for a budget processor, but certainly not high end.

but pair it with a low power gpu and you can certainly do some light gaming.

i see..i heard many peoples said that this cpu is good for light gaming..is there any ways to increase the performance of this processor besides overclocking?can i get your wise opinions sir?

Nope. No way to increase its performance. It's not bad, but of course there are better CPUs out there.

Agree with the above. Pair it with a low or mid range CPU and you will get decent results. Something like a HD6850 will balance it off nicely.

Also,

can i ask you one question?what is the middle budget gpu that can suit to this processor?ddr3 or ddr5?

gtx 460 or a 6850, they are often pretty cheap and well tested. As for the cpu it would be nice to know what code they used for the firmware in the cpu that defines the multiplier, voltage, and other settings. It is all software unlike the old days but oh well  

i see...thanks for that valuable knowledge! and one more question,from what i read on the internet,i saw some peoples said that if we want to unleash the hidden potential of the g620,intel will charge us about 30 dollars for that.is it true?and what is the hidden potential hidden in this tiny procesor?

Yes. It's called a G860.

the intel G620 cpu is a decent cpu
its clock rates go between1.6ghz and up to 2.6ghz
intel created this series cpu's as a cheap series for decent performance for a budget build.

to get the best performance out of it.
in bios disable
intel speedstep technology
and cpu c1E

this will make the cpu run at clockrate 2.6ghz 24/7
so now the cpu will run at max performance.

but now the tempurature will be high, so make sure you have a lot of fans in your case.
and make sure that in bios you Change the fans from Cool&Quiet to max performance.