I am curious about the advantages & disadvantages of overclocking a single core/all cores of my i7 5930K.

I had the idea due to a badly optimized game that is seeing a CPU bottleneck in my current setup, sadly it only uses one core so the oc on all the other cores pretty much goes to waste.

My idea was to overclock one core (core 0 for example) to a higher clock (5 GHz as an example) and that I leave the other cores at boost clock and then go ahead and assign the game to core 0 and the rest of the system to cores 1-5.

The question is though how would this go stability, voltage and heat wise?

Current OC is 4.7 GHz @ 1.335 Volts

Specs:

i7 5930K

Zotac GTX 980Ti AMP Extreme Edition

Msi X99S SLI Plus

Xilence 1000w modular series