With all the hype surrounding Steam Machines at this year's CES, it's easy to forget that purchasing a brand new system isn't the only way to check out Valve's vision for the future of PC gaming. The Linux-based operating system powering Steam Machines, SteamOS, is available to download free of charge directly from Valve. Given its beta status, only certain hardware is currently supported, and setting it up does involve a bit of Linux know-how. But with just a little work, it's relatively easy to build your own Steam Machine, or convert an existing Windows PC into one--you can even dual boot.

Currently, SteamOS only supports PCs with Intel processors and Nvidia, Intel, or AMD graphics cards. Laptops that feature both discreet and integrated graphics aren't currently supported. You'll also need at least a 500GB hard disk, and 4GB of RAM, but most PCs from the last few years will make the cut.

Our test rig is an Ivy Bridge Intel i5-powered PC, complete with 8GB of DDR3 1333Mhz RAM. We used two GPUs for testing, AMD's high-end R9 290 X and an older Nvidia GTX 670. It's not the highest spec PC out there (in terms of the processor at least), but for the purposes of comparing a performance across operating systems it'll work a treat. We're using two identical WD 1TB Caviar Green drives in the system: one with Windows 7 64 installed, and the other with SteamOS. This helps make dual booting between the two operating systems as painless as possible.

There are two versions of SteamOS available: one with less configuration required that restores an image of SteamOS to your PC, and another that runs through a standard OS setup. The restoration version requires that you have a 1TB hard drive fitted. If you're using a smaller drive like a fast SSD for example, you need to go through the standard setup, which is what we opted for here.

Installation

Once you've downloaded the installer from the Steam website, extract the contents of it to a USB stick. You'll need one around 2GB or more in size. Plug it into your PC and then boot from the USB stick by opening the boot selection screen at startup (keep an eye on your computer's boot screen for a prompt). You should be presented with a list of boot options. Select the UEFI entry for your USB drive, and the SteamOS installer will boot up.

Select "Automated Install" and the installer will wipe the contents of your hard drive, partition it, and install SteamOS. The process takes around 30 minutes. During installation you may run into an issue with your display going to sleep and not waking up again if you're plugged in via HDMI, so if possible go in via DVI. If that's not an option, keep an eye on your hard drive activity light. If it has stopped blinking for any amount of time, it's relatively safe to power off your PC, remove the USB stick, and then turn it on again. If all goes well you should be presented with a login screen.

If your display looks like this after boot, clicking the button on the top right will make the text legible.

Again, if you're plugged in via HDMI, you may encounter an issue with the screen resolution being incorrect upon boot, making the text illegible. The solution (other than to plug in via DVI) is to hit the icon nearest you on the top right of the screen and click the top option. This makes the text bigger, allowing you select the "Gnome" session from the login window and login with the username and password "steam" (minus the quote marks).

If when you reach the Linux desktop your screen resolution is still incorrect, you need to go into the settings and configure your display. Swipe your mouse over "Activities" on the top left of desktop, select applications, then system settings, then display settings. The bottom of the window with the OK button may be off the screen, in which case you need to tab through the options a few times using the keyboard to confirm your selection. Next you need to get Steam installed. Open up Terminal from the applications window, type in "steam" and then press enter. Once Steam is installed, close the open windows and logout of the system.

Login to the Gnome session again, this time using the username "desktop" and the password "desktop". Open up another terminal window and type in "~/post_logon.sh". Terminal will prompt you for a password, which is also "desktop". The system will automatically reboot and create a recovery partition. Once that's done the system will reboot again and you'll finally be presented with the Steam login screen!

Unfortunately, we encountered another issue when we connected via HDMI that caused an incorrect resolution to be displayed in Steam. To fix this, you need to enable access to the desktop by going into the settings by clicking the gear icon at the top right of the screen, selecting "Interface", and then checking "Enable access to the Linux desktop". Now when you click the power button at the top right you'll be presented with an additional "Return to Desktop" option.

To fix an incorrect resolution in Steam's Big Picture mode, you need to modify /usr/bin/steamos-session with the highlighted line.

On the desktop open up another terminal window, then enter "sudo nano /usr/bin/steamos-session". You'll likely be asked for your password, which will again be "desktop". This opens up a text file that you can scroll through using the arrow keys. Find the line that says "Preload", press enter to create a new line, and then type in "xrandr -s 1920x1080", replacing 1920x1080 with your preferred resolution. Hit Ctrl and X on your keyboard and then Y to save the file. After a restart you should be presented with the correct resolution.

While that might seem like a lot of effort to go to in order to get things working, in the grand scheme of Linux, SteamOS fares pretty well. Everything aside from the correct screen resolution worked straight away, including things like audio and the Ethernet port, components that traditionally require a bit of terminal fiddling to get working. Even swapping out an Nvidia card for an AMD one didn't throw up any issues, with the system automatically recognizing the card without the need to install additional drivers.

If you're setting up a dual boot system and like us are using two physical drives, unplug the SteamOS drive, plug your other one in, and go through the standard Windows setup. Leaving the other drive plugged in would mean Windows would overwrite the default Grub bootloader for SteamOS with its own, and while you can fix it with a bit of Windows and Linux magic (as found here), this method is far simpler. Once Windows is installed, plug the other back in and you'll be able to switch between the two systems using the default boot selection screen built into your motherboard.

Performance

Currently, there's only a limited selection of games that have actually been ported to SteamOS. The Linux section of the store is mostly populated with indie titles, the exception being Valve's own games like Left 4 Dead 2, as well as the likes of Football Manager and Metro: Last Light. All the games we tried worked well, but for the purpose of benchmarking between Windows and SteamOS we stuck with the more graphically intensive Left 4 Dead 2, Metro: Last Light and DOTA 2.

AMD R9 290 X Windows FPS @ 1080p SteamOs FPS @ 1080p Dota 2 120 48 Left 4 Dead 2 242 182 Metro: Last Light 68 24

Nvidia GTX 670 Windows FPS @ 1080p SteamOS FPS @ 1080p Dota 2 120 120 Left 4 Dead 2 200 172 Metro: Last Light 37 45

Each game was run with identical settings across both operating systems. Metro: Last Light offers fewer configuration options in SteamOS than in Windows, but a quick dig into the configuration text file let us match the two up as closely as possible.

Looking at the R9 290 X results, there's clearly an issue with the card under SteamOS. In Windows, it performs brilliantly, just as we'd expect for such a high-end GPU But there's something amiss about AMD's drivers under Linux that's causing the R9 290 X to underperform. We also noticed stuttering while playing Left 4 Dead 2 under Linux, which made the game frustrating to play. Hopefully these issues can be resolved in a future driver update or version of SteamOS. In the meantime, though, potential SteamOS users might want to make sure they're packing an Nvidia GPU before making the jump.

The older Nvidia GTX 670 performed very well in Windows and in SteamOS. Indeed, in Left 4 Dead 2, the card actually performed better under SteamOS. It's not better by a huge margin, but it's a great result for Linux, particularly given the traditionally meagre GPU driver support for the OS that caused a certain Linus Torvalds to give Nvidia the finger.

Despite this, though, there are still some issues to be overcome with SteamOS. We noticed significantly longer loading times for Left 4 Dead 2 and Dota 2 than in Windows, for instance, and general performance through the UI isn't as snappy as big picture mode on Windows. There's also the matter of the more complex setup to deal with, and, most importantly, the limited game selection.

Still, SteamOS is a beta release, and with time there's no doubt that Valve will be able to squeeze more performance out of Linux and streamline the setup process. Best of all, it's free! That alone might be enough to convince some to ditch the $100 Windows licence and turn to SteamOS for gaming. And who knows? If enough people install it or buy a Steam Box, there may even be more than a handful of games to play on it too.