So before asking this here I did some research and I found some answers but I have no idea what's right. The official page of Steam box says:
You can play all your Windows and Mac games on your SteamOS machine, too.
But then I read posts of some people for example:
http://www.tomsguide.com/us/steamos-faq-machines,news-17614.html
That says:
Q.: What games run on SteamOS?
A.: Any Steam game with Linux support should run on SteamOS, although Valve will pin
down this list as the launch date approaches. There are roughly 300 Linux games
available through Steam, including major titles like "Europa Universalis IV" and
indie darlings like "Fez."
And some forum posts about not buying it because you can't play windows games.
So I am confused now. Can you or can you not play windows games on the Steambox / Steam OS?
Best Answer
The functionality being referenced when talking about playing Windows games on Steam OS (which is a Linux derivative) is not currently present in the current releases of Steam OS. The functionality in question is actually licensed from Nvidia and is the same streaming technology used in the Nvidia Shield, and will appear in Steam OS closer to its official release.
This technology doesn't allow you to "play" Windows games as much as it allows the heavy lifting to be performed on a Windows machine on your local network and then streamed to the box running Steam OS.