Software & Firmware
Software
We were surprised to find that the Z170 Gaming-ITX/ac does not include ASRock’s F-Stream overclocking utility, nor is it listed in the App Shop download options. It is available on the board's download page though, and provides both programmed and manual overclocking functions
Overclocking tools are firmware-based and include basic overclocks of 4.4-4.8 GHz with corresponding voltage levels of 1.26 to 1.45V, approximate. "Gear Levels" add a DDR4-2400 DRAM O/C to 46 and 4.7 GHz overclocks, and enable the "Auto Tuning" feature. Manual settings are available within the range supported by firmware, which in turn is limited by hardware.
ASRock's Fatal1ty series motherboards include a three-month Premium service upgrade for XSplit streaming services, free access to XFast LAN by cFos, and a one-month Ultimate upgrade to Orbweb.me.
Firmware
Z170 Gaming-ITX/ac firmware opens to "EZ Mode" settings, which include an XMP-enabled switch, mode selection for the integrated SATA controller, a basic 4.4 GHz overclock setting for our Core i7-6700K, and several of the utilities detailed below.
Many of the features included in F-Stream / A-Tuning are also included in firmware, such as System Browser to show detected hardware, and OMG network access time limits. Other firmware utilities include message transmission to ASRock technical support, Easy RAID Installer for copying drivers from ASRock's CD to your own thumb drive, Easy Driver Installer, Instant Flash firmware updates via thumb drives, and Internet Flash firmware update downloads.
ASRock's OC Tweaker menu provides all of the "Optimized Overclocks" shown in F-Stream, but without the "Gear Ratio" settings. Submenus offer access to advanced overclocking controls.
Our CPU reached its normal 4.60 GHz overclock at 1.30V CPU core, which is a pretty good result for such a compact voltage regulator. A few full-sized boards weren't this stable.
Memory overclocking wasn't as easy; though only one board has ever surpassed this memory's rated DDR4-3600 in a review, it generally scales a little higher than the DDR4-3200 max stable data rate seen in the Z170 Gaming-ITX/ac.
Finding a 1.30V CPU core setting under load was a little tricky, since none of the "Load-Line Calibration" settings were perfect. Level 2 load-line calibration pushed "CPU Vcore" upward slightly under load, but combining that with a 1.295V baseline got it to our target.