A new Taiwanese startup has built a new concept motherboard with the CPU socket on its backside. This might seem weird, but the point of it is to make it possible to place a passive CPU cooler on the outside of the chassis, leading to noiseless operation, as spotted by FanlessTech.
The company that has dared to challenge the norm is Enctec, and their current prototype applies this concept to a relatively standard ATX chassis. The end result is quite an empty case with a big bulge on its right side.
Of course, the end result here seems quite impractical -- it doesn't make effective use of the case's internal space, and as FanlessTech also points out, the chassis has enough ventilation holes to pull off a passive CPU cooler on the inside, making the reversing a bit unnecessary.
Nevertheless, we do think that Enctec is onto something with its reverse-socketed motherboard. Not for a system as showcased, but one where the motherboard sits on a spine inside the case. Chuck the GPU on a riser on the 'normal' side of the motherboard, and CPU cooling on the reverse side of the chassis, and you end up with a system that has an internal layout that's somewhat reminiscent of the Xbox Series X's internals with cooling hardware on both sides of the mainboard.
The motherboard packs a B250 chipset and Intel LGA1151 socket, so it's not exactly up to snuff with today's hardware -- but that obviously isn't the point with this prototype.