Overclocking only one core?

[killerloader]

I saw an option in my motherboard to set 'per core' values for overclocking/turbo, although i read in a lot of places that it doesn't work, it has allowed me to overclock to 4.8GHZ (When i could usually only get to 4.5GHZ)
And I have seen massive speed improvements, with lower temperatures.
Basically i underclocked every core, and overclocked a single core, and it runs really well...

Is there anything wrong with this, and why do so many people say it doesn't work?

I have tested games, and they work a whole lot better!