Comma.ai Launches Chestnut eGPU Dock to Boost Autonomous Driving AI Performance

Comma.ai has launched the "chestnut" external eGPU dock for $249 (or $799 bundled with an AMD Radeon RX 9060 8GB GPU) to upgrade the AI inference capabilities of its comma four device. The dock increases the device's power limit from 10W to 100W, enabling it to run a new 1-billion-parameter model in the upcoming openpilot 0.11.2. This hardware expansion allows open-source autonomous driving systems to run much larger AI models, bringing comma four's computing power close to Tesla's proprietary HW4 platform. It represents a novel, modular approach to scaling edge AI compute in consumer vehicles without replacing the main hardware unit. The chestnut dock utilizes a PCIe Gen4 x4 to USB4 bridge architecture, with its control chip firmware written in C and published on GitHub by the tinygrad organization. The new 1B-parameter model offers a 30x increase in parameters and a 100x increase in floating-point operations compared to the standalone comma four.