ArsTechnica reports that the SteamOS open beta has added built-in support for Intel and AMD GPUs following the reveal earlier this week of 12 Steam Machine partners at the Consumer Electronics Show.
Nvidia, Intel, and AMD GPUs power all of these devices.
An AMD representative's email suggested that SteamOS is running Catalyst 13.11 Beta 9.9 drivers and that AMD's support website would soon offer a standalone driver package.
Intel GPUs utilise Mesa 10.0.1. Both Intel and Nvidia GPUs are supported but dual-GPU Optimus solutions are not currently compatible.
Previous SteamOS builds all used Nvidia driver support by default, including the 300 Steam Machine beta units distributed by Valve which included various types of GeForce GPUs.