# Bonsai-27B Brings 1-Bit Quantization to Local Inference

> A ternary-weight 27B model with hybrid attention aims to run large-model reasoning on everyday hardware.

Published by The Open Weights on Jul 4, 2026. Canonical: https://theopenweights.com/news/bonsai-27b-lf5s

## Key facts

- Company: Prism Ml
- Model: Bonsai-27B
- Version: 1.0
- Category: Text / LLM
- Modalities: Text / LLM
- License: Other (Open weights, commercial use allowed)
- Parameters: 27B
- Context window: 262K tokens
- Architecture: qwen35
- Significance: notable
- Published: 2026-07-04
- Last verified: 2026-07-23
- Hugging Face: https://huggingface.co/prism-ml/Bonsai-27B-gguf
- Canonical URL: https://theopenweights.com/news/bonsai-27b-lf5s

The prism-ml team has released [Bonsai-27B](https://huggingface.co/prism-ml/Bonsai-27B-gguf), a 27-billion-parameter text model designed to run locally through aggressive quantization. Rather than shipping full-precision weights, the release leans on 1-bit and ternary quantization paired with a hybrid attention scheme, distributed in the GGUF format that has become the standard for CPU and consumer-GPU inference.

The pitch is straightforward: fit a model in the 27B class onto hardware that would normally struggle with it. Ternary weights—values constrained to roughly {-1, 0, 1}—dramatically shrink the memory footprint compared to 16-bit or even 4-bit representations, and hybrid attention can trim the compute cost of long sequences. Together, those choices are aimed squarely at on-device use.

## Why it matters

Most of the excitement around low-bit models has centered on smaller architectures. A 27B model that targets ternary quantization is a more ambitious test of whether extreme compression can hold up at scale.

- **Format:** GGUF, ready for common local runtimes
- **Size:** 27B parameters, in the 13B–34B tier
- **Approach:** 1-bit/ternary weights plus hybrid attention

Several specifics remain unstated, including the model's context length and licensing terms, which are listed only as "other." Anyone considering it for production work will want to verify those details and evaluate quality directly, since extreme quantization always involves trade-offs against a full-precision baseline. The weights and documentation are available now on [Hugging Face](https://huggingface.co/prism-ml/Bonsai-27B-gguf).

## Get the model

- [Hugging Face](https://huggingface.co/prism-ml/Bonsai-27B-gguf)

## Sources

- [prism-ml/Bonsai-27B-gguf](https://huggingface.co/prism-ml/Bonsai-27B-gguf) — Hugging Face, Jul 4, 2026

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Source: The Open Weights (https://theopenweights.com/). Aggregated and written by Claude, curated by humans. Cite as: "Bonsai-27B Brings 1-Bit Quantization to Local Inference", The Open Weights, Jul 4, 2026, https://theopenweights.com/news/bonsai-27b-lf5s