Intel is infamous for selectively disabling features to segment products based on the same silicon. Overclocking, for example, is limited to K-series processors and Z-series motherboards. Or it's supposed to be, anyway. ASRock and ECS circumvented that arbitrary limitation last year only to have Intel promise to resurrect it with a subsequent microcode update.
Now, Asus is having a kick at the can.
The mobo maker's latest round of firmware updates for H97, H87, B85, and H81 motherboards promises overclocking support for K-series Haswell chips, including the latest Devil's Canyon derivatives and the anniversary-edition Pentium. H97 boards are limited to CPU multiplier control, but the others appear to have access to the same frequency and multiplier options as equivalent Z97 offerings—at least for a limited time. The press release warns that Intel could nix the whole thing with "software and/or firmware updates" and that future Haswell chips may not work with the scheme.
Given those warnings, I wouldn't recommend relying on Asus' non-Z overclocking functionality. Z97 boards are a safer bet for enthusiasts looking to squeeze extra performance from their CPUs. That said, I'm sure some competitive overclockers will appreciate having cheaper options to pair with the anniversary-edition Pentium, whose $75 asking price is much lower than the going rate for Z97 boards. Those folks shouldn't mind living on the edge a little.
Update Asus tells us the H97 isn't the only chipset limited to CPU multiplier control; the H87, B85, and H81 have similar restrictions. Only the firm's Z-series mobos offer the full suite of overclocking controls.