@Mellon Head the stock speed is 3,6,but currently it's on 4,0 .
What voltage do you recommend me ? Also,could you please explain me what voltages exactly are ,since I am not that good in understanding how PC's actually work.
I'm afraid I can't recommend any voltage. I don't know what the max is, and it would be irresponsible for me to do that. It might wreck your hardware if I tell you a voltage that is too high for your chip. I'd feel bad about that if it happened.
I can explain the voltage, though. The CPU uses a small voltage for power, among other things. It has a nominal value, like say for example 1 Volt. (And keep in mind that these are only examples.) That might be the voltage the CPU uses at it's normal clock speed, and everything works wonderfully. When you're overclocking, the CPU needs more power, so sometimes you have to "bump" up the voltage a little bit, say 0.025 Volts to get it to be stable at the new clock frequency. So now we're at 1.025 Volts and the computer is running fine. Let's say we want to increase the clock speed a little more, so we add 0.025 Volts more to get it to be stable again at the new frequency. Now, we're at 1.05 Volts. With the added voltage comes more heat that the CPU has to dissipate. The more voltage you add, the more heat gets generated, and the faster the CPU clock runs, the more heat gets generated. This is why you need good cooling if you are going to overclock.
When overclocking, you can only add so much voltage before you hit a wall. You reach your maximum stable overclock, and adding more voltage doesn't help, and will likely wreck the processor. The better your cooling, (usually) the higher your maximum stable overclock will be, but it's a very fine line between maximum and damaging your CPU. That's why you never want to go over your max VCore voltage. It will damage the CPU very quickly if you do. The key is very small steps, but you have to know the limit to start with to make sure that you don't go over it. In your case, the limit isn't published. Googling the limit only gave me values that other people had tried with, but not a published specification. Personally, I would prefer to go with a published spec than someone's say so. It's safer.
My advice to you, if you really want to overclock your PC and you have limited knowledge about how they actually work, is to read as much about it as you can BEFORE doing it. Go to overclocking forums and learn what you are doing. Then, and only then, OC your rig. There is a lot more to it than just jacking the multiplier and voltages up. It's a fine art that must be done carefully if you don't want to have to replace your hardware.
That's the end of my sermon for today.