Motherboard maker ASRock released UEFI updates to their Intel 8-series H87 and B85 chipset motherboards, featuring Non-Z OC technology, which allows to overclock Intel Haswell K processors, in essence, the i5 4670K and i7 4770K (and some future SKUs) on the mentioned chipset motherboards. According to ASRock, their H87 and B85 motherboards allow up to 26% clock boost over their competitor H87 and B85 motherboards.
The first motherboard to implement Non-Z OC feature is ASRock Fata1lty H87 Performance, which, despite H87 chipset, should be overclocking-friendly due to 8-phase CPU power design.
To enable Non-Z OC, all current owners of ASRock H87 or B85 motherboards and Intel Haswell K CPUs need to do, is update their motherboards' UEFI to the latest version, boot into BIOS, set the desired multiplier, and voila! According to ASRock, clocks reached with H87 and B85 motherboards are no lower than those with Z87. That said, reaching 4.8 GHz with a good K chip and proper cooling is possible. Average chips should be able to get to 4.5 GHz or so.
Now, if only they released the good old Non-K OC for Haswell, so those who need could have them running at high clocks while retaining advanced features which are locked in overclockable K models - TSX-NI, vPro and VT-d technologies.
