Workstation rather than server, this is basically a normal BabyAT board with (limited) onboard I/O that could even be stuck into a generic cramped minitower case. A server-oriented board would probably have EISA instead of ISA, probably no onboard I/O and might well be larger to accommodate more RAM.

As for "rare" - any dual So5 board is uncommon, I'd say this is one of the more frequently seen, well-documented and liked boards.

Bear in mind that in 1994-1995 the number of operating systems that could actually sensibly use SMP was very limited - so the use cases for a system like this were similarly limited. Basically this would have been used for a Windows NT 3.5 workstation, probably for CAD/CAM applications. And before you ask, it's pointless for gaming, no games that would run on an So5 CPU use SMP. It would have had 'snappier' general desktop performance than a single So5 board (in NT 3.5 or similar SMP OS), but that alone would never have justified the very significant added price of this SMP board and the second CPU.

I've been wanting one of these, but not willing to pay the eBay price. These use the Neptune chipset, which is kind of an oddball being both rare and at the time pretty expensive. This board does not support EDO DRAM or pipelined burst cache, so it's somewhat slow compared to the Triton based boards. Unless you're going for period correct, for a dual board you might want one based on 430HX.