There's a fairly convincing argument to be made that AMD's Ryzen Threadripper CPUs are best suited for workstations rather than gaming rigs. AMD and Nvidia might be downplaying the relevance of multi-GPU gaming, but multi-GPU compute acceleration is bigger than ever. If you've a mind to build a Threadripper-based compute box, have a look at ASRock's X399 motherboard offerings. The company's first two Socket-TR4 motherboards are the Fatal1ty X399 Professional Gaming and the X399 Taichi. Both will accept up to four graphics cards in their metal-reinforced PCIe x16 slots.
Threadripper has a ton of PCIe connectivity on tap, but obviously ASRock didn't spend all of its 64 lanes on those main PCIe slots. If you install four cards in either board, you'll end up with two running at x16 and two running at x8. That leaves plenty of lanes for the 802.11ac Wi-Fi adapter, triple M.2 sockets, U.2 port, and dual Intel gigabit Ethernet connections that both boards have. The Fatal1ty X399 board also has an Aquantia AQC107 chip onboard to support 10-Gigabit Ethernet, giving it a total of three wired LAN connections.
Both new boards fill the standard ATX form factor, a notable fact among the stack of competitors' Threadripper boards that billow out to the larger E-ATX size. Either board will take up to 128GB of DDR4 memory operating at 3600MT/s, although ASRock only guarantees operation at 2667 MT/s. The boards appear to be similar in terms of power delivery hardware, too. Both feed the hungry Threadripper CPU with an 8-pin EPS12V connector as well as a second 4-pin ATX12V connector.
The primary differences in the two boards (besides the visual design) appear to be the aforementioned Aquantia network controller and the X399 Fatal1ty's support for Creative Sound Blaster Cinema 3 audio DSP effects. The X399 Taichi even retains the onboard power and reset buttons, the no-CPU-required BIOS Flashback feature, and the RGB LEDs of its sibling. Of course, they'll probably differ in price, too, but we'll have to wait until we find them in shops to know.