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Bonsai-1.7B-mlx-1bit
End-to-end 1-bit language model for Apple Silicon
12.8x smaller than FP16 | 4.6x faster on M4 Pro | 130 tok/s on iPhone | runs on Mac, iPhone, iPad
Highlights
- Deployed footprint — runs on virtually any Apple device
- End-to-end 1-bit weights across embeddings, attention projections, MLP projections, and LM head
- MLX-native format (1-bit g128) with inline dequantization kernels — no FP16 materialization
- Cross-platform companion: also available as GGUF Q1_0_g128 for llama.cpp
Resources
- Google Colab — try Bonsai in your browser, no setup required
- Whitepaper — for more details on Bonsai, check out our whitepaper
- Demo repo — comprehensive examples for serving, benchmarking, and integrating Bonsai
- Discord — join the community for support, discussion, and updates
- 1-bit kernels: MLX fork (Apple Silicon) · mlx-swift fork (iOS/macOS) · llama.cpp fork (CUDA + Metal)
- Locally AI — we have partnered with Locally AI for iPhone support
Model Overview
Quantization Format: 1-bit g128
Each weight is a single bit: 0 maps to −scale, 1 maps to +scale. Every group of 128 weights shares one FP16 scale factor.
MLX's quantization formats generally store both a scale and a bias per group: w = mlx_scale * bit + mlx_bias. To pack our scale-only 1-bit weights into this format:
This reconstructs −scale when bit=0 and +scale when bit=1. Because MLX stores two FP16 values per group (scale + bias) instead of one, the effective bits per weight is slightly higher than the GGUF format:
- MLX 1-bit g128: 1.25 bpw (1 sign bit + two 16-bit values amortized over 128 weights)
- GGUF Q1_0_g128: 1.125 bpw (1 sign bit + one 16-bit scale amortized over 128 weights)
Memory Requirement
Parameter memory only (weights and scales loaded into memory):
The model directory on disk is ~0.28 GB (~16 MB larger) because it also includes tokenizer, config, and other metadata files alongside the weights.
Best Practices
Generation Parameters
System Prompt
You can use a simple system prompt such as:
Quickstart
MLX (Python)
Requires PrismML fork of MLX with 1-bit kernel support (upstream PR pending):
MLX Swift (iOS / macOS)
1-bit Bonsai 1.7B runs natively on iPhone and iPad via MLX Swift. Requires our mlx-swift fork with 1-bit kernels (upstream PR pending).
Throughput (MLX / Apple Silicon)
Citation
If you use 1-bit Bonsai 1.7B, please cite:
Contact
For questions, feedback, or collaboration inquiries: contact@prismml.com