This number still isn't too different from prior months unless debating tenths of a percent. Ubuntu 13.10 64-bit continued to be the most popular Linux distribution used at 0.37% followed by Ubuntu 12.04.4 LTS and then Linux Mint 16. The OS X Steam usage was at 3.42%.
These numbers aren't much of a surprise given past months results and there still being no real change within the Linux gaming community. There's now hundreds of Steam Linux games out there, but no compelling reason yet for Windows gamers to completely abandon Windows and switch to Linux. SteamOS is still in beta and the Steam Machines aren't shipping en mass. Hopefully later in 2014 the Steam results will be much more interesting for Linux, especially as more game studios take interest in Linux. We'll see later this month at GDC. The latest non-gaming web stats also put the overall desktop Linux market-share at right around 2%.
With the Steam Hardware Survey results now allowing to be broken down by OS, it shows that NVIDIA is most popular for Linux gamers with 52% use, Intel at 16%, and AMD at 31%. Intel processors are mostly present at 74%. Most Linux gamers are running with just 4GB of RAM and two CPU cores.
The survey results in full can be found via the SteamPowered.com Hardware Survey page.