The problem with being on the cutting edge of Intel's CPU technology is that the latest CPU cores are always reserved for its mainstream CPU interfaces. It takes another half-generation for high-end models to get replaced, and the replacement is often a full generation behind mainstream counterparts. The notion that Intel can spend a product cycle or two perfecting its cores before unleashing them on the server market makes sense from a business standpoint, but it typically leaves enthusiasts to choose between faster mainstream technologies or higher-core-count server-based parts.
Since most games make little use of a fifth core (let alone a seventh or eighth), it makes sense to pick a quad-core CPU with the best per-core performance and highest possible clock. Both of those features are exclusive to the top CPUs of Intel's "mainstream" class, which today is represented by the Core i7-6700K. On the other hand, Intel's "professional" platforms provide the best connectivity for multiple graphics cards. Since mainstream users don't need more than a single PCIe 3.0 x16 slot, Intel equips its mainstream platforms that way. And since users who would pair the fastest-possible quad-core processor with three or four of the fastest-possible graphics cards are only a tiny fraction of the overall market, Intel virtually ignores these builders.
The workaround for connecting multiple graphics cards to the Core i7-6700K and other Skylake-based desktop processors is to use a repeating switch, as already discussed in our EVGA Z170 Classified review. Labeled "Multicast" by the switch's manufacturer, this part takes advantage of CrossFire and SLI's need to send identical data to every card by repeating sixteen controller lanes to two sets of sixteen device lanes. Too expensive for mid-budget performance enthusiasts, this part is usually bundled with other high-end features to create a premium package. Though high-end in every respect, EVGA had a tough time filling-out its Z170 Classified with a broad-enough features set to match our expectations for the $400+ premium market.
Unlike its above-mentioned competitor, Gigabyte's Z170X-Gaming G1 has no trouble presenting enough features to qualify it as a "premium class" product by nearly any definition. Advancements begin with Intel's DSL6540 Thunderbolt 3 controller, which replaces the ASM1142 USB 3.1 controller found on the Z170 Classified while simultaneously adding a myriad of connection possibilities.
Gigabyte also added an 802.11ac MIMO Wi-Fi controller with up to 867mbps bandwidth, while retaining dual Gigabit Ethernet capability. The company also didn't drop the ASM1142 from its controller set, instead it was moved to a PCIe-based (via SATA-E) front-panel device.
We even see a pair of G1/4 fittings to connect the Z170X-Gaming G1's 22-phase voltage regulator to an open-loop liquid cooler.