SteamOS—Valve’s invasion into the gamer’s living room—has entered beta phase and is now available for download. The installer of this new Linux-based operating system is close to 1GB in size and can be tested for free.
Pretty much everything you need to know about installing SteamOS are answered in a FAQ page (links below). To get it up and running, you’ll need a gaming rig powered by an NVIDIA graphics card (Intel and AMD cards are not supported for now), a 64-bit processor from either Intel or AMD, 4GB of RAM, a USB port, and a 500GB (or larger) hard disk. A fair bit of warning, though: it’s best to use a spare (preferably newly bought) hard drive so as not to affect your main drive containing your documents and your PC’s important files.
As a viable alternative to popular gaming consoles (like the Sony PlayStation), SteamOS is Valve’s plan to liberate its library of games from the PC platform and deliver it to the living room. That said, Windows games and apps that are without Linux support are not compatible with Valve’s platform, although a streaming feature over a local network is being developed.
[Source: Download SteamOS, Install FAQ]