PrismML27B~5 GB VRAM at 1-bit (binary, ~1.125 bpw)

1-bit Bonsai 27B — VRAM, speed & local setup

Written by Jakub Rusinowski · Last updated

The phone build. Binary {−1, +1} weights at ~1.125 bits/weight bring a full 27B multimodal model down to 3.9 GB — small enough to run on an iPhone 17 Pro at ~11 tok/s. PrismML reports it keeps more than 90% of the FP16 baseline (MATH 91.66, coding 81.88); tool-calling is the weak spot, dropping from ~80 to ~66. Ships as GGUF (llama.cpp / LM Studio) and MLX (Apple). Specs from launch coverage — verify on the Hugging Face model card.

1-bit Bonsai 27B needs about 5 GB of VRAM at 1-bit (binary, ~1.125 bpw) — quantized weights plus framework overhead, before any KV cache. On Apple Silicon that figure comes out of unified memory.

Logic87
Creative80
Coding85

VRAM and speed by quantization

Quoted against NVIDIA RTX 4090 (24 GB). Weights plus overhead only: this model's architecture is unpublished, so no KV cache is added.

QuantVRAMSpeed (est.)Fit
1-bit (binary, ~1.125 bpw)
1.13 bpw
4.6 GB~119 tok/sFits

Black marker = usable memory on the NVIDIA RTX 4090 (24 GB). Estimates from the memory-bandwidth roofline on the methodology page. 1-bit Bonsai 27B VRAM calculator →

Get 1-bit Bonsai 27B running

The cheapest catalogued GPU that runs 1-bit Bonsai 27B is the Intel Arc B570 (10 GB).

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Intel Arc B570 10GB
10 GB VRAM · 150 W board power
2026 prices are volatile — check the current listing.

How to run 1-bit Bonsai 27B

Install Ollama, then run:

ollama run bonsai-27b
Weights on Hugging Face: prism-ml/Bonsai-27B-gguf ↗

Specifications

Preview — The model is released, but these specs are thin or rest on a single source. Individual fields may be wrong.

Preview — The model is released, but these specs are thin or rest on a single source. Individual fields may be wrong.

Parameters
27 Billion
Context window
262,144
Architecture
Qwen3.6-27B (multimodal), 1-bit binary weights
Provider
PrismML
Licence
Apache 2.0
Practical deployment
Edge device (phone, SBC)
Specified at
1-bit (binary, ~1.125 bpw)
System RAM
8 GB
Record updated
2026-07-15
LicenceApache-2.0Commercial use permitted

Commercial use permitted. No usage restrictions beyond attribution.

Quality and use cases

Scores as published by the model’s authors or an independent evaluator — quality, not throughput, and not measured by us.

Best foron devicephoneofflinemultimodalreasoning
BenchmarkScoreProvenance
MATH91.66 %vendor-claimed · PrismML (launch)
Coding (HumanEval+ class)81.88 %vendor-claimed · PrismML (launch)
Tool-calling (BFCL class)66 %vendor-claimed · PrismML (launch)

Can I run 1-bit Bonsai 27B on my GPU?

Other Bonsai 27B sizes

1-bit Bonsai 27B — frequently asked questions

How much VRAM does 1-bit Bonsai 27B need?

About 5 GB at 1-bit (binary, ~1.125 bpw) — quantized weights plus framework overhead, before any KV cache. The cache grows with context length and is added on top; the table above folds it in. Apple Silicon counts unified memory toward the same figure.

Does 1-bit Bonsai 27B run on an RTX 4090 (24 GB)?

Yes. 1-bit Bonsai 27B needs about 5 GB at 1-bit (binary, ~1.125 bpw), inside a 24 GB card, at an estimated 119 tokens/sec.

How do I run 1-bit Bonsai 27B locally?

Install Ollama and run `ollama run bonsai-27b`. That pulls the weights and starts a local OpenAI-compatible endpoint; after the download nothing leaves the machine.

What other sizes does Bonsai 27B come in?

1-bit Bonsai 27B (5 GB), Ternary Bonsai 27B (7 GB). Every size shares the family's training and licence; the larger ones score higher and need proportionally more memory.