Turbo I believe on that cpu is 4.7, 4.6, 4.6, 4.5GHz, so technically locking all the cores to 4.7GHz is an overclock. But Intel Always sets stock voltages far higher than is necessary. Not every cpu responds the same, all are different, so Intel sets voltages to cover Every cpu, no matter what its actual needs are. If your cpu requires 1.10v, someone else's might run 1.18v or 1.08v, so Intel sets 1.25v just in case.
Meaning, you could leave everything at stock settings, lock the multiplier and most probably still be good.
OC isn't getting faster speeds on all cores, it's getting the best performance for the best temps at the best voltages.
The stock setting on my i5-3570k is @ 1.25v at 3.7GHz turbo. I ran it at 1.14v at 4.3GHz locked core. Temps compared to stock went down over 15°C by overclocking the cpu and lowering voltages. My i7-3770K stock was @ 1.25v turbo 3.8GHz. OC was 1.32v locked core 4.9GHz. Only a small bump in voltage for a 1.1GHz all core OC.
You do not necessarily have to add voltages with OC. What you should be doing is testing to see how low you can get voltages, while remaining stable. That's the reason for LLC, disable some c-states, disable phase controllers etc.
If you want to successfully OC and get the best from the cpu, you need to research OC and how to do it correctly, tips, tweaks, do's and don't's, what does work, what doesn't work etc for both your motherboard and that cpu. OC is OC, it's the same theory, doesn't matter if it's msi or gigabyte or asus, it's all the same, just name changes. Asus might call it vcore, Msi call it cpu voltage, same thing. Research everything, read everything, watch everything.
Then OC.