I recently bought a new cooler for my CPU (Be Quiet! Pure Rock) and I was thinking about overclocking my i5-2500k in order to squeeze some extra performance out of the 4-year-old chip. But since I haven't got the most suited motherboard I'm not sure if I wan't to increase the voltages on the CPU, but instad only increase the core clock and leave the base voltage as is.
Is this possible or do I have to increase the voltages, and could extra voltage harm the system? If it is possible, how many Megahertz could I expect to get out of it?