"The Maximus VIII Impact is a mini-ITX motherboard, and most people don't associate the two with extreme overclocking. However, since the board only has two DIMMs, prior experience would indicate much higher memory overclocking margins than four DIMM motherboards. ASUS backs this with 4133MHz memory support, and my testing seems to confirm easy XMP with higher frequency DDR4 kits. Moving the VRM to a daughterboard also allows for a much higher performance VRM, and the Maximus VIII Impact's VRM rivals that of many Z170 motherboards. BIOS support for extreme overclocking is also present, and all the OC features you need are pretty much present."
Steven Bassiri - TweakTown.
ASUS Maximus VIII Impact review by TweakTown - Introduction & Conclusion.