---
title: Introducing chestnut
link: https://blog.comma.ai/chestnut/
source: blog-comma-ai
published: 2026-08-12T21:00:00Z
updated: 2026-08-12T21:00:00Z
first_seen: 2026-09-19T21:30:23.395188495Z
summary: Upgrade your comma four’s compute to run openpilot’s biggest models. Today, we’re launching chestnut, a compute upgrade for comma four. Want to run big models? Nothing beats a desktop GPU. We’re also launching the first chestnut-class model, which is …
content: extracted
html: 2026-08-12-introducing-chestnut.html
preview:
  file: 2026-08-12-introducing-chestnut.preview-1d4314ba6ae9.webp
  width: 256
  height: 134
  alt: Cover
  color: '#706c6a'
images:
- source: https://blog.comma.ai/img/chestnut/cover.jpg
  original:
    file: 2026-08-12-introducing-chestnut.image-f31f29aeb102.jpg
    width: 1200
    height: 629
  color: '#14161a'
- source: https://blog.comma.ai/img/chestnut/ready_34.png
  original:
    file: 2026-08-12-introducing-chestnut.image-4636dccde3d2.png
    width: 1600
    height: 1600
  variants:
  - file: 2026-08-12-introducing-chestnut.image-b546e92f8149.webp
    width: 320
    height: 320
  - file: 2026-08-12-introducing-chestnut.image-60128ee20895.webp
    width: 640
    height: 640
  - file: 2026-08-12-introducing-chestnut.image-e3d46a764c07.webp
    width: 960
    height: 960
  - file: 2026-08-12-introducing-chestnut.image-b0467f9ce63f.webp
    width: 1280
    height: 1280
  - file: 2026-08-12-introducing-chestnut.image-afb9fe949f7b.webp
    width: 1600
    height: 1600
  color: '#26262b'
- source: https://blog.comma.ai/img/chestnut/ready_left.png
  original:
    file: 2026-08-12-introducing-chestnut.image-6cbb34e78e9a.png
    width: 1600
    height: 1600
  variants:
  - file: 2026-08-12-introducing-chestnut.image-1237aa374794.webp
    width: 320
    height: 320
  - file: 2026-08-12-introducing-chestnut.image-f36adb69446e.webp
    width: 640
    height: 640
  - file: 2026-08-12-introducing-chestnut.image-00c290731f86.webp
    width: 960
    height: 960
  - file: 2026-08-12-introducing-chestnut.image-6120d4d121ba.webp
    width: 1280
    height: 1280
  - file: 2026-08-12-introducing-chestnut.image-37a941d4f4db.webp
    width: 1600
    height: 1600
  color: '#383636'
- source: https://blog.comma.ai/img/chestnut/ready_front.png
  original:
    file: 2026-08-12-introducing-chestnut.image-b6ccc97eafe7.png
    width: 1600
    height: 1600
  variants:
  - file: 2026-08-12-introducing-chestnut.image-5df1d944b020.webp
    width: 320
    height: 320
  - file: 2026-08-12-introducing-chestnut.image-cf4dcf88d409.webp
    width: 640
    height: 640
  - file: 2026-08-12-introducing-chestnut.image-cf2be5b5b648.webp
    width: 960
    height: 960
  - file: 2026-08-12-introducing-chestnut.image-2dd4ee31eb7b.webp
    width: 1280
    height: 1280
  - file: 2026-08-12-introducing-chestnut.image-051142d6f63c.webp
    width: 1600
    height: 1600
  color: '#26262a'
- source: https://blog.comma.ai/img/chestnut/ready_right.png
  original:
    file: 2026-08-12-introducing-chestnut.image-4411c941f7b5.png
    width: 1600
    height: 1600
  variants:
  - file: 2026-08-12-introducing-chestnut.image-548b665e3053.webp
    width: 320
    height: 320
  - file: 2026-08-12-introducing-chestnut.image-0ede300d2284.webp
    width: 640
    height: 640
  - file: 2026-08-12-introducing-chestnut.image-4a63295533a0.webp
    width: 960
    height: 960
  - file: 2026-08-12-introducing-chestnut.image-ee2ae0c93cf3.webp
    width: 1280
    height: 1280
  - file: 2026-08-12-introducing-chestnut.image-a51b85e4d56d.webp
    width: 1600
    height: 1600
  color: '#1b1c22'
- source: https://blog.comma.ai/img/chestnut/ready_back.png
  original:
    file: 2026-08-12-introducing-chestnut.image-25a74781893e.png
    width: 1600
    height: 1600
  variants:
  - file: 2026-08-12-introducing-chestnut.image-e8b782706ab7.webp
    width: 320
    height: 320
  - file: 2026-08-12-introducing-chestnut.image-fa8d250527f2.webp
    width: 640
    height: 640
  - file: 2026-08-12-introducing-chestnut.image-c04c811c49a2.webp
    width: 960
    height: 960
  - file: 2026-08-12-introducing-chestnut.image-28742c1be94a.webp
    width: 1280
    height: 1280
  - file: 2026-08-12-introducing-chestnut.image-97f84713a980.webp
    width: 1600
    height: 1600
  color: '#242328'
- source: https://blog.comma.ai/img/chestnut/bignuts.png
  original:
    file: 2026-08-12-introducing-chestnut.image-3dba0c353290.png
    width: 2600
    height: 1800
  color: '#f7f8f9'
- source: https://blog.comma.ai/img/chestnut/comma_four_windshield.png
  original:
    file: 2026-08-12-introducing-chestnut.image-ac5e99e4aa54.png
    width: 1253
    height: 728
  variants:
  - file: 2026-08-12-introducing-chestnut.image-294da31c8c33.webp
    width: 320
    height: 186
  - file: 2026-08-12-introducing-chestnut.image-e4ec99d9ddd7.webp
    width: 640
    height: 372
  - file: 2026-08-12-introducing-chestnut.image-f398273dfac6.webp
    width: 960
    height: 558
  - file: 2026-08-12-introducing-chestnut.image-890fd5b57e7e.webp
    width: 1253
    height: 728
  color: '#07050a'
---

*Upgrade your comma four’s compute to run openpilot’s biggest models.*

![Cover](https://blog.comma.ai/img/chestnut/cover.jpg)

Today, we’re launching [chestnut](https://comma.ai/shop/chestnut), a compute upgrade for comma four. Want to run big models? Nothing beats a desktop GPU. We’re also launching the first chestnut-class model, which is bigger than all openpilot driving models we’ve released combined.

![chestnut ready to drive from a three-quarter angle](https://blog.comma.ai/img/chestnut/ready_34.png) ![left side of chestnut ready to drive](https://blog.comma.ai/img/chestnut/ready_left.png) ![front of chestnut ready to drive](https://blog.comma.ai/img/chestnut/ready_front.png) ![right side of chestnut ready to drive](https://blog.comma.ai/img/chestnut/ready_right.png) ![back of chestnut ready to drive](https://blog.comma.ai/img/chestnut/ready_back.png)

### Scaling beyond intelligence density [Permalink](https://blog.comma.ai/chestnut/#scaling-beyond-intelligence-density "Permalink")

Since the beginning, openpilot has led on intelligence density. For the last 10 years, we’ve shipped increasingly capable driving models in an on-device compute footprint of 10 W. We shipped fully [end-to-end lateral planning](https://blog.comma.ai/end-to-end-lateral-planning/), experimental [end-to-end longitudinal planning](https://blog.comma.ai/090release/#experimental-mode), and even a point-to-point demo to [Taco Bell](https://blog.comma.ai/taco-bell).

Over the last two years, we rewrote our stack to scale efficiently with compute and data. With the [MLSim architecture](https://blog.comma.ai/mlsim), more driving data and training compute translate directly into better openpilot models. The comma fleet now logs nearly one million driving minutes every day, and our scaled-up data pipeline ingests 15% of those drives into the training cluster.

Bigger models need more compute to run. With chestnut, openpilot is scaling beyond cellphone-sized inference compute. A comma four paired with chestnut has similar compute to Tesla HW4.

#### A new 1B driving model [Permalink](https://blog.comma.ai/chestnut/#a-new-1b-driving-model "Permalink")

We’re launching chestnut with a new 1B parameter driving model in the upcoming openpilot 0.11.2 release. It’s our biggest model yet, and the first in a new line of chestnut-class models.

![Bignuts](https://blog.comma.ai/img/chestnut/bignuts.png)

Compared to the latest on-device model, the first chestnut-class model has 30x more parameters, 100x more FLOPs, and room to go even bigger. Going forward, our autonomy team will focus primarily on maximizing the capabilities of chestnut-class models, and we expect this new class of model to increase development velocity.

#### Ready to Drive [Permalink](https://blog.comma.ai/chestnut/#ready-to-drive "Permalink")

chestnut comes in a convenient ready to drive kit, which includes chestnut, an AMD Radeon RX 9060 8GB, and everything needed to power, connect, and mount it in your car.

![Comma four windshield](https://blog.comma.ai/img/chestnut/comma_four_windshield.png)

The GPU mounts out of the way in the passenger footwell or under the passenger seat. Run the included cable to comma four, connect to your car’s cigarette lighter, and you’re ready to run openpilot’s biggest models.

## Get your chestnut [Permalink](https://blog.comma.ai/chestnut/#get-your-chestnut "Permalink")

chestnut is available today in the [comma shop](https://comma.ai/shop/chestnut).

- chestnut ready to drive is available now for $799.
- tiny chestnut is available now for $249 for use with your own GPU.
- Both versions come with a 30-day money-back trial and a one-year hardware warranty.

Excited about scaling up? Join us in the **#hw-chestnut** channel on [Discord](https://discord.comma.ai)!

*Want to help scale up openpilot? We’re [hiring](https://comma.ai/jobs) for autonomy, product, and operations.*