ASRock's latest batch of motherboard BIOS updates remove the SKY OS function, which permitted overclocking of non-K Intel processors via BCLK (baseclock).
The news comes amid speculation that Intel had pressured motherboard vendors to remove such functionality. Intel's unlocked K parts (i5-6600K, i7-6700K) will once again be the only options for Skylake overclocking on Z170 on ASRock boards (assuming prior BIOS versions are no longer available), and with no Pentium G3258 this generation Intel is no longer a budget friendly option for enthusiasts looking to push their CPU past factory specs.
(Image credit: Hexus.net)
It sounds like now would be a good time to archive that SKY OS enabled BIOS update file if you've downloaded it – or simply refrain from this BIOS update. What remains to be seen of course is whether other vendors will follow suit and disable BCLK overclocking of non-K processors. This had become a popular feature on a number of Z170 motherboards on the market, but ASRock may have been in too weak a position to battle Intel on this issue.