Model reference · open weights

stablelm-2-zephyr-1

LLMs stabilityai Text gen 1 build Its own licence terms 11k dl/mo

stablelm-2-zephyr-1 is an open-weight language model from Stability AI. stablelm-2-zephyr-1_6b (FP16) weighs 1.2 GB; the smallest configuration that runs it is RTX 3060 12 GB.

  • StableLM 2 Zephyr 1.6B is a 1.6 billion parameter instruction-tuned language model developed by Stability AI for text generation tasks.
  • The model supports English and is distributed under the StabilityAI Non-Commercial Research Community License.
  • It is an auto-regressive transformer decoder architecture that was fine-tuned using Direct Preference Optimization.

Summary of the stabilityai/stablelm-2-zephyr-1_6b model card, 2026-10-01

What it is

Released byStability AI
Released2024-01-19
Parameters1.6B
VRAM1.2 GB for the weights

What it runs on

Memory and cards for stablelm-2-zephyr-1_6b (FP16)

1.2 GBweights, file size
197 MBcache per 1K tokens
556 MBruntime overhead, at least
4,096 tokenscontext max
CardRequests at onceContext maxMemory
4K each
RTX 3060 12 GB12all 4K11.6 GB
RTX 4060 Ti 16 GB16all 4K15.4 GB
RTX 3090 24 GB26all 4K23.4 GB
RTX 4090 24 GB26all 4K23.4 GB
RTX 5090 32 GB36all 4K31.0 GB
L40S 48 GB52all 4K44.0 GB
A100 80 GB94all 4K78.2 GB
H100 80 GB94all 4K78.1 GB
RTX PRO 6000 Blackwell 96 GB114all 4K93.8 GB
DGX Spark (GB10) 128 GB unified131all 4K107 GB
H200 141 GB169all 4K138 GB
B200 180 GB216all 4K176 GB
Memory needed at each load
Requests at once4K tokens each
12.5 GB
55.8 GB
88.2 GB
1614.6 GB
3227.5 GB
6453.3 GB

One card, with vLLM's small-card settings.

From the model card

What Stability AI says about stablelm-2-zephyr-1

Read the model card

Model Description

Stable LM 2 Zephyr 1.6B is a 1.6 billion parameter instruction tuned language model inspired by HugginFaceH4's Zephyr 7B training pipeline. The model is trained on a mix of publicly available datasets and synthetic datasets, utilizing Direct Preference Optimization (DPO).

Usage

StableLM 2 Zephyr 1.6B uses the following instruction format:

Which famous math number begins with 1.6 ...?
The number you are referring to is 1.618033988749895. This is the famous value known as the golden ratio

This format is also available through the tokenizer's apply_chat_template method:

from transformers import AutoModelForCausalLM, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained('stabilityai/stablelm-2-zephyr-1_6b')
model = AutoModelForCausalLM.from_pretrained(
    'stabilityai/stablelm-2-zephyr-1_6b',
    device_map="auto"
)

prompt = [{'role': 'user', 'content': 'Which famous math number begins with 1.6 ...?'}]
inputs = tokenizer.apply_chat_template(
    prompt,
    add_generation_prompt=True,
    return_tensors='pt'
)

tokens = model.generate(
    inputs.to(model.device),
    max_new_tokens=1024,
    temperature=0.5,
    do_sample=True
)

print(tokenizer.decode(tokens[0], skip_special_tokens=False))

Model Details

Training Dataset

The dataset is comprised of a mixture of open datasets large-scale datasets available on the HuggingFace Hub:

  1. SFT Datasets
  • HuggingFaceH4/ultrachat_200k
  • meta-math/MetaMathQA
  • WizardLM/WizardLM_evol_instruct_V2_196k
  • Open-Orca/SlimOrca
  • openchat/openchat_sharegpt4_dataset
  • LDJnr/Capybara
  • hkust-nlp/deita-10k-v0
  1. Preference Datasets:
  • allenai/ultrafeedback_binarized_cleaned
  • Intel/orca_dpo_pairs

Performance

MT-Bench

ModelSizeMT-Bench
Mistral-7B-Instruct-v0.27B7.61
Llama2-Chat70B6.86
stablelm-zephyr-3b3B6.64
MPT-30B-Chat30B6.39
stablelm-2-zephyr-1.6b1.6B5.42
Falcon-40B-Instruct40B5.17
Qwen-1.8B-Chat1.8B4.95
dolphin-2.6-phi-22.7B4.93
phi-22.7B4.29
TinyLlama-1.1B-Chat-v1.01.1B3.46

OpenLLM Leaderboard

ModelSizeAverageARC Challenge (acc_norm)HellaSwag (acc_norm)MMLU (acc_norm)TruthfulQA (mc2)Winogrande (acc)Gsm8k (acc)
microsoft/phi-22.7B61.32%61.09%75.11%58.11%44.47%74.35%54.81%
stabilityai/stablelm-2-zephyr-1_6b1.6B49.89%43.69%69.34%41.85%45.21%64.09%35.18%
microsoft/phi-1_51.3B47.69%52.90%63.79%43.89%40.89%72.22%12.43%
stabilityai/stablelm-2-1_6b1.6B45.54%43.43%70.49%38.93%36.65%65.90%17.82%
mosaicml/mpt-7b7B44.28%47.70%77.57%30.80%33.40%72.14%4.02%
KnutJaegersberg/Qwen-1_8B-Llamaified*1.8B44.75%37.71%58.87%46.37%39.41%61.72%24.41%
openlm-research/open_llama_3b_v23B40.28%40.27%71.60%27.12%34.78%67.01%0.91%
iiuae/falcon-rw-1b1B37.07%35.07%63.56%25.28%35.96%62.04%0.53%
TinyLlama/TinyLlama-1.1B-3T1.1B36.40%33.79%60.31%26.04%37.32%59.51%1.44%

Training Infrastructure

  • Hardware: StableLM 2 Zephyr 1.6B was trained on the Stability AI cluster across 8 nodes with 8 A100 80GBs GPUs for each nodes.
  • Code Base: We use our internal script for SFT steps and used HuggingFace Alignment Handbook script for DPO training.

Use and Limitations

Intended Use

The model is intended to be used in chat-like applications. Developers must evaluate the model for safety performance in their specific use case. Read more about safety and limitations below.

L

Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.

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