chestnut

$799

Shipping

Free US shipping, $30 flat rate internationally.

Using chestnut with openpilot?

Choose ready to drive for everything you need to add desktop-class GPU compute to your comma four.

Try our 30-day money-back trial

We think you’ll love chestnut, but if you’re not satisfied, send it back within 30 days for a full refund.

1-year hardware warranty

1-year limited warranty against hardware defects.

Meet chestnut

chestnut is a compute upgrade for comma four, built for bigger models. It connects a desktop GPU directly to your comma four, giving openpilot the compute to run its biggest driving models. The first chestnut-class model has 30x more parameters and uses 100x more FLOPs than the latest on-device model.

The ready to drive kit is the easiest way to bring that compute into your car. tiny chestnut and ready to drive use the same USB-to-PCIe board and run the same open-source custom firmware.

Read the launch blog post.

Using chestnut

Annotated connection diagram of the chestnut board

With a PC

USB4

Connect chestnut to your computer and use it like any other USB4 dock.

USB3 or USB2

Use tinygrad to access the GPU over a USB3 or USB2 connection.

Mac

Follow the TinyGPU setup guide to use a supported GPU on macOS.

Join the #gpu-on-usb channel on the tinygrad Discord.

With openpilot

Pair chestnut with comma four to run openpilot’s biggest models. The ready to drive kit includes everything you need for an in-car setup: a GPU, a longer USB cable, a car power cable, and mounting strips.

Join the #hw-chestnut channel on Discord.

In the Box

tiny chestnut

$249

chestnut

1m USB4

standoffs + thumb nuts

ATX power adapter

GPU power cable

ready to drive

$799

chestnut

1m USB4

standoffs + thumb nuts

ATX power adapter

GPU power cable

AMD Radeon RX 9060 8GB

3m USB3

car power cable

mounting strips

Setup Guide

Step 1 of 7

Install the standoffs

Thread the two standoffs into chestnut’s base so they are ready to support and secure the GPU.

Step 2 of 7

Connect power to chestnut

Plug the GPU power cable into chestnut before installing the GPU.

Step 3 of 7

Seat the GPU

Align the GPU with chestnut’s PCIe slot and press it firmly into place.

Step 4 of 7

Secure the GPU

Align the GPU with the standoffs and secure it with the thumb nuts.

Step 5 of 7

Connect GPU power

Plug the other end of the 8-pin power cable into the GPU.

Step 6 of 7

Mount in your car

chestnut and GPU mounted in the passenger footwell — Mount in the footwell

chestnut installed under the passenger seat — Or install under the passenger seat

Secure the assembled chestnut and GPU in the passenger footwell with the included mounting strips, leaving room for airflow. If there’s enough room, you can also install chestnut under the passenger seat.

Step 7 of 7

Plug it in

chestnut vehicle power adapter plugged into the car — Connect vehicle power

USB cable connected to comma four — Connect comma four

Connect chestnut to vehicle power and plug the USB cable into your comma four.