Once upon a time, before anyone had ever even imagined there would be dual-core CPUs, the truly hardcore PC enthusiasts were building and overclocking dual-CPU machines. The legendary Abit BP6 and similar dual-socket boards were popular choices for the task, and my best friend once built (and overclocked) a machine using a monstrous Tyan Thunder K7. We thought those days were long gone, but perhaps not. Have a glance at the Asus WS-C621E-Sage. You may want to sit down first.
That thing in the picture is exactly what you think it is: a motherboard with a pair of spots for Xeon Scalable Processors sitting in LGA 3647 sockets (aka Socket P). The board has one DIMM slot per memory channel per CPU, for a total of twelve RAM slots. Builders can install up to 768 GB of ECC RDIMMs or LR-DIMMs running at up to 2666 MT/s, if they can find such exotic equipment. The board can run four PCIe 3.0 x16 expansion cards at full bandwidth, or three x16 cards and four more with x8 connections. There are four U.2 connectors and an M.2 socket on the board, all of which get four lanes of PCIe 3.0 to play with (although we're not sure whether there's some lane-sharing going on). There are even ten SATA 6 Gbps ports.
Okay, so what? None of those specs are weird for a workstation board. What's out of the ordinary here is that Asus explicitly describes the WS-C621E-Sage as an overclocker's board. Asus doesn't have the board's CPU support list up yet, so we don't know exactly exactly which Xeon SP chips it can overclock. Still, that feature alone makes the Sage unique, to our knowledge.
The Sage is funky in other ways, too. It has a fair few features you won't normally find on this sort of motherboard, like a pair of USB 3.1 Gen 2 ports in Type-A and Type-C formats, and a CMOS reset button on the rear panel. Further overclocking features include on-board power and reset buttons, as well as a diagnostic LED readout. The board's high-end audio hardware appears to be a close relative of the ROG SupremeFX solution found on Asus' fancy gamer boards. The paired Intel Gigabit Ethernet controllers are less unusual, as is the onboard Aspeed AST2500 chip that provides basic video output from the board's VGA port.
We've just spotted the product page for the WC-C621E-Sage on Asus' site, so we don't know when you'll be able to plunk down your pound of flesh for it. The motherboard hasn't showed up at e-tail yet, but if you intend to build a monument to excess you probably don't care what it will cost when it does.