I think the Turbo Boost stuff also works for when all 4 cores are used. On my G55 i7-3630QM CPU-Z regularly shows 3.2ghz when CPU is 100% eg. rendering stuff.
In any case I've never had problems with WatchDogs, Borderlands, COD:AW, Batman, etc. Make sure you install the game on an SSD though, to prevent any hiccups during playing.
With 660M overclocked as well I can more or less max out COD:AW which for a laptop is... insane. 660M on my G55 can go up to 1100mhz core/ 3000mhz mem... This is with NO CPU OC which means CPU is 3.2ghz standard.
Edit: Here is CPU-Z for OC'ed with Intel Extreme Tuning Utility i7-3660QM showing running clock speed at 3.3ghz. Cheers
🙂Edit2: 3.3ghz OC IS NOT STABLE FOR ME! I'M TRYING 3.25GHZ NOW
🙂