Introducing chestnut

Comma four users can now upgrade their device to run openpilot's most advanced models with the launch of chestnut, a new compute upgrade tailored for comma four. This upgrade allows for the execution of large-scale models that would otherwise require a desktop GPU. In addition to the chestnut upgrade, openpilot is rolling out its first chestnut-class model, which is significantly larger than any of the driving models previously released by openpilot combined.

Openpilot has consistently prioritized intelligence density since its inception ten years ago, delivering increasingly capable driving models while maintaining an on-device compute footprint of just 10 W. In recent years, the company has restructured its architecture to efficiently scale with increased compute and data. This led to the creation of the MLSim architecture, which enables a direct correlation between the volume of driving data, training compute, and the resulting improvement in openpilot's models.

The comma fleet logs an impressive one million driving minutes daily, with 15% of that data contributing to the training cluster. However, to run these more complex models, a greater amount of computational power is needed. Chestnut addresses this need, enabling openpilot to surpass the computing capabilities of cellphone-sized inference. When paired with a comma four, chestnut delivers compute power comparable to Tesla's HW4.

The first chestnut-class model is set to be released alongside the chestnut upgrade as part of the upcoming openpilot 0.11.2 release. This new model boasts 30 times more parameters, 100 times more FLOPs, and ample room for even greater expansion. Going forward, openpilot's autonomy team will concentrate on maximizing the capabilities of chestnut-class models, anticipating a boost in development velocity.

Chestnut is conveniently packaged in a ready-to-drive kit, which includes the GPU, AMD Radeon RX 9060 8GB, and all necessary components for installation and connection to the comma four. The GPU is designed to mount discreetly in the passenger footwell or under the passenger seat, and connecting it to the comma four via the included cable is all that's required to begin running openpilot's most advanced models. Chestnut is currently available for purchase on the comma shop.