Valve have teased us quite a bit in the last couple of weeks with its unveiling of the Steam Box, Steam OS and Steam Machines, with the latter being announced with NVIDIA GPUs.
Most thought that the Steam Machines would run AMD GPUs too - like myself - but this wasn't full confirmed, leaving many to believe that maybe, just maybe, NVIDIA had secured a very tight contract with Valve. The Half-Life developer has come out and confirmed that the Steam Machines would indeed support the three primary graphics vendors today.
Valve spokesperson, Doug Lombardi, said: "Last week, we posted some technical specs of our first wave of Steam Machine prototypes. Although the graphics hardware that we've selected for the first wave of prototypes is a variety of NVIDIA cards, that is not an indication that Steam Machines are NVIDIA-only. In 2014, there will be Steam Machines commercially available with graphics hardware made by AMD, NVIDIA, and Intel. Valve has worked closely together with all three of these companies on optimizing their hardware for SteamOS, and will continue to do so into the foreseeable future."