Comma AI releases chestnut — a 100-watt compute unit for openpilot...

Comma AI releases chestnut — a 100-watt compute unit for openpilot with a 1-billion-parameter model

Comma AI introduced chestnut — a PCIe Gen4 x4 to USB4 bridge with open firmware and a 1-billion-parameter control model, scaling openpilot to the level of Tesla HW4.

Compiled by Sergey KostenchukPublished 2026-08-14Updated 2026-09-18

2026-08-14 Business

🚗 Comma AI introduces chestnut — a powerful unit for openpilot

The device scales the comma four compute system from 10 to 100 watts — to the level of Tesla HW4. New control model: 1 billion parameters, 30 times larger than before. Configurations: tiny chestnut ($249) and chestnut ready to drive with AMD Radeon RX 9060 ($799).

🌍 Comma AI demonstrates a path to scaling autonomous driving — instead of miniaturizing models into a 10-watt chip, the project moves to desktop GPUs through an open USB4 bridge with public firmware.

👤 The device is already on sale in the Comma AI store, with a 30-day return policy and a one-year warranty. For developers — a rare example of an open stack: firmware, the tinygrad framework instead of PyTorch, and the model.

Source 1: https://blog.comma.ai/chestnut/

Source 2: https://www.phoronix.com/news/Comma.ai-PCIe-Gen4-USB4-Dock

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