The Z170-HD3 doesn’t even have the PCIe pathway switches needed to go from single x16 to dual x8 graphics modes, nor is it locked into dual x8 mode, so SLI certification would have been impossible. Instead, the second x16-length slot is fed by four of the chipset’s PCIe 3.0 lanes, but remember that the total bandwidth of this chipset’s CPU link is already limited to that same 32Gbps bandwidth as the second slot.
There’s also the six-phase voltage regulator, which will limit how much power can go into the CPU and thus prevent insane overclocked frequencies, at least at full CPU load. We’re anxious to see where its power limit kicks in.
All those feature reductions have allowed Gigabyte to significantly shrink the Z170-HD3 below the standard ATX specification — down to 7.8” front-to-back. Slots are still spread across the full ATX slot panel, though.
Proving that Gigabyte takes criticism extremely well, the firm has moved both USB 3.0 front-panel headers to the upper half of the Z170-HD3, where many of its previous products had at least one of those headers situated under a graphics slot. They’ve also slid the front-panel audio header forward by about a quarter-inch, which might make a few of those “too-short” front panel cables long enough.
The M.2 slot is slid up close to the CPU socket, which means that it'll probably be difficult to access with a large CPU cooler installed. We rarely need to access our M.2 slots anyway, so this was probably a good choice. Sliding it this close to the CPU socket means that there’s room for a PCIe x1 slot in the top position, rather than below the graphics card where it would get blocked by the GPU cooler.
Gigabyte was even courteous enough to put SATA-Express connectors on all six SATA ports, though you’ll lose one of those ports if you happen to be using a SATA-based M.2 drive.
Lacking any serious concerns regarding motherboard layout, we turn to the Z170-HD3 installation kit and find no worries again. Gigabyte includes only two SATA cables, but that should be forgivable for any motherboard that uses a Z-series chipset and costs only $115. At this price, the target market has but two drives.