Right now called the "Piston".





It's made of 3 small motherboards that can be upgraded as more things are developed later.
This thing can apparently play games like Crysis 2. It wasn't told at what settings but if it's doing it at max that's outstanding.
Apparently it can also support up to 4K resolution. Probably upscaled.

They have 3 varieties right now.
The Z3RO ProDual-Core 64-bit @ 1.65GHz
4GB DDR3
16GB-1TB flash based SSD
Dual Monitor Support
15 Watt TDP
X5A ModularNot much is said about it, probably a scaled down version of X7A
30 Watt TDP
X7A ModularQuad-Core 64-bit @ 2.8GHz - 3.2GHz
64GB-1TB SSD
Has Radeon 7000 series GPU with 384 programmable graphics cores
Triple Monitor support
40 Watt TDP
So after they announced their thing Steam was interested in the technology behind it and went ahead to invest into it. Xi3 will not be their steambox but more like a 'prototype' or example. They want to have something more powerful.
Now people like me are skeptical about this. How can this not heat up. If my computer gets really hot playing a game, how would this keep any cooler playing the same game. It's not happening. I know the things are smaller in size but it still won't stop it from getting really hot. It doesn't make sense. Also it can cost up to $1000. I rather build a cutom PC with that money and get something better.
Also they are trying to get linux on this. Really bad choice here because of AMD's lack of support for Linux.
References;
Xi3 Main SiteSteam investment into Xi3More about the thingPictures/discuss