So yeah - my CPU voltages right now stand at 1.000V with the auto-overclock settings, but I want to get a 4GHz overclock. I have a Coolermaster Hyper 212+ heatsink which will suffice nicely for the goal I want to achieve. I just need to know what's a safe voltage for my CPU (the max safe voltage).
The absolute maximum voltage for that processor as specified by Intel is 1.400v, you NEVER want to go over that voltage (at least if you want a long term OC), otherwise you end up degrading the CPU in a shorter time period (I've heard 3-12 months before degradation is apparent quoted before). I personally would try to aim for voltages below 1.3v to reduce wear and heat. Probably the best thing would be to start with VCC at 1.10 or there about, and then work it up in increments until stable.