When Intel launched their Haswell processors back in June the overclocking features were only available to K-series chips that were used on Z87 motherboards. Overclocking was not made available to other motherboards with the H87 or B85 chipsets. I guess the reasoning behind this was to get many using to get the more expensive Z87 motherboard route rather than the less expensive H87 or B85 motherboards.
Since the introduction of Haswell many motherboard manufacturers have been able to get around this restriction on H87 and B85 motherboards. ASRock was the first with the Non-Z OC feature and it was followed by Gigabyte, ASUS, Biostar, MSI and ECS. What this feature does is it allows users with a K-Series Haswell processor to overclock the chip on a H87 or B85 motherboard.
Intel does not seem to happy about motherboard manufactures finding a way around their restriction and is said to be releasing a firmware update for their H87/B85 motherboard chipsets. This firmware update would actively block the Non-Z OC feature from various manufacturers. There is no official word on whether Intel will be offering the update or if Intel is making motherboard manufacturers include the update in their latest BIOS update.