Intel's Skylake-based Xeon E3-1200 v5 CPUs aren't meant for consumer-focused chipsets like the Z170 or H170. Instead, those workstation CPUs need motherboards based on the workstation-focused C230 series chipsets. Gigabyte has a quartet of motherboards based on that line, and the flagship has some interesting expansion options.
The MW31-SP0 has the traditional PCI-Express x16 slots that you might expect, but this ATX motherboard also includes an expansion slot with four PCIe 3.0 lanes that can accept mezzanine cards with additional ports. Expansion options include a 10-gigabit Ethernet controller, extra M.2 slots, and a combination Thunderbolt and DisplayPort adapter.
This workstation-focused motherboard also packs a pair of Intel Gigabit Ethernet controllers, support for two-way SLI and CrossFireX, an M.2 slot, and eight SATA 6Gbps ports. Since the MW31-SP0 is based on the C236 chipset, it supports up to 64GB of ECC DDR4 memory across its four DIMM slots.
All of the other motherboards Gigabyte introduced for the Skylake-based Xeons use the C232 chipset. The MW21-SE0 is for entry-level workstations. This microATX board also supports 64GB of ECC DDR4 memory, but it only includes a single Intel Gigabit Ethernet controller, six SATA 3.0 ports, and one PCI Express x16 slot. A second x16 slot gets four lanes of PCIe.
Gigabyte also unveiled a pair of server-oriented motherboards, the Mini-ITX MX11-PC0 pictured above and the Micro-ATX MX31-BS0. Both motherboards would be good fits for rack-mounted servers, thanks to their low-profile rear port configuration. The MX11-PC0 eschews M.2 slots in favor of a U.2 port, but also packs four SATA 6Gbps ports and support for 32 GB of ECC DDR4 memory. The larger MX31-BS0 brings M.2 back, along with six SATA 6Gbps ports and support for 64 GB of memory. These boards also sport Intel Gigabit Ethernet controllers.