Reddit user Large_Customer_3840 has successfully connected an AMD Radeon RX 9070 XT to a Valve Steam Machine using an Aoostar EG01 eGPU dock. The setup utilizes an M.2-to-OCuLink adapter connected to the internal M.2 slot, enabling a PCIe 4.0 x4 connection.
To facilitate the build, the internal PCIe SSD was moved to an external USB-C enclosure for booting SteamOS. The Radeon RX 9070 XT was recognized as the primary GPU without manual configuration, though the case must remain open due to a lack of cable routing.
This modification significantly boosts performance over the integrated RDNA-3 GPU. In testing, the system achieved over 100 FPS in Crimson Desert on High settings, demonstrating the potential for high-end external graphics on Valve's compact gaming hardware.