For yonks, rumours have buzzed about Valve selling its own pre-built PC, fondly nicknamed the 'Steam Box' by fans. Yesterday Valve and Xi3 announced that the Half-Life creator and Steam mastermind had invested in the fledgling hardware company, and that the pair are working on a mini-PC aimed at living rooms with the codename 'Piston.'

The Piston is a diddy little PC intended to plug into your living room screen and run games in Steam's Big Picture mode. Xi3's thing is modular computers which you can upgrade by switching modules out, looking far less intimidating than upgrading a big desktop box. The company hasn't revealed Piston's specs yet, but told Polygon it's based on its X7A model.

Starting at around $1,000, the X7A packs a Quad-Core processor with 384-core integrated graphics, which I'd haphazardly guess is AMD's A10 series. It boasts 4GB or 8GB of RAM, oodles of USB ports, and four eSATAp ports for extra external storage. Now, Piston's specs and price won't necessarily line up, but this gives a fair idea of what to expect.

Xi3 attempted to Kickstart its boxes in 2012, but fell far short of the $250,000 crowd-funding goal. Exactly how much Valve invested in Xi3 and what it gets in return is unknown.

Valve head honcho Gabe Newell commented in December that bringing Steam to Linux would be a boon for its then-still-not-officially-announced living room PCs, so Linux should be an option. "Certainly our hardware will be a very controlled environment," he said at the time. "If you want more flexibility, you can always buy a more general purpose PC." Yep, that's the X7A all right.

So, Valve has the best PC digital distribution platform, which looks grand on televisions, and now a shiny little PC to sit in your living room. Interesting times ahead for PC gaming.

Here's a video from October, looking at Xi3's modular hardware:

[Story image snapped by Polygon, which has more photos too.]