I am planning on getting the new i3 3220. Now I know the i3 has a locked multiplier and cannot be fully overlocked, but I am really only looking for a small overclock. How much can you overlock the i3 3220 before it cuts you off? Also, is it possible to unlock the i3?
you can't OC nor can you unlock an i3 (as far as i can tell). even if you do plan to raise the base clock, the performance gains would be too small for you to notice, and you're more likely to be annoyed by the system instability, than happy over the OC.
consider a Phenom II x4 955BE/965BE, FX-4300/6300 if you feel like OCing on a budget.
I've seen tons of reviews of this CPU. Most of clearly point out that it is possible to overlock this CPU, just not very much, becasue the multiplier on it has been locked and set very short
You can't overclock and there's no review that says that's possible, you're mistaken with the partially locked i5 cpus that can be bumped 400 mhz over the maximum turbo boost frequency, but with the i3-3220 you can't overclock or raise the frequency at all.
Generally speaking, the only way I know of to OC a Core i3 is to increase the BCLK frequency. However, it cannot be increased very much because all devices have their frequencies tied to the BCLK.
From what I've read the PCI-e slot and especially the USB ports are rather sensitive to the BCLK frequency and the general recommendation is not to increase the frequency by more than 5Hz or 6Hz and that excessive increase can permanently damage the USB ports.
Overclocking the BCLK on Sandy/Ivy Bridge CPUs is a fools' errand. Even if by some miracle you managed 103MHz and kept stability, multiply that by the i3-3220's 33x multiplier and you've got 99MHz (exactly one multiplier's worth).
Here's what you can expect on current Ivy Bridge models:
i3 - Fully-locked multiplier
i5/i7 (non-K models) - Partially-locked multiplier (can go up by 4 multipliers max)
i5/i7 (K models) - Fully-unlocked multiplier (stability subject to voltage and thermal barriers imposed by the chip's physical design).