Yes. But it all depends on how much you overclock and which i5 you have. It will vary from different processors. For example, the i5 3570k overclocked to 4.2ghz can use 1.15 or so Volts. May vary on different ones. Keep in mind, you will never want to exceed 1.3V as it can seriously damage your CPU. Also, BIOS is the best way of overclocking. Adding on to that, you must have a Motherboard which is compatible with overclocking. If you have a motherboard not compatible for overclocking, there's no way you can overclock to a certain extent. Research all these before attempting. Post which i5 you are looking at and your motherboard as well as how much you want to overclock and the CPU Cooler.