I believe there are some BIOS updates out there that will allow it, but I don't think it applies to every board. Check around on the ASRock forums and support pages.
Intel has also promised to disable this unintended feature, possibly through a driver update in Windows or by having manufacturers suppress BIOS updates.
That said, normally all you would have available is BCLK modification, but if you can get the ability to change the multiplier, then you could change the turbo mode max ratio to overclock. Potentially reaching 4.3Ghz or more. Various guides exist for overclocking, not sure if I know of an ASRock specific one, but I've used this Gigabyte guide for basic information...