Model reference · open weights
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.
Summary of the stabilityai/stablelm-2-zephyr-1_6b model card, 2026-10-01
What it is
| Released by | Stability AI |
|---|---|
| Released | 2024-01-19 |
| Parameters | 1.6B |
| VRAM | 1.2 GB for the weights |
What it runs on
| Card | Requests at once | Context max | Memory |
|---|---|---|---|
| 4K each | |||
| RTX 3060 12 GB | 12 | all 4K | 11.6 GB |
| RTX 4060 Ti 16 GB | 16 | all 4K | 15.4 GB |
| RTX 3090 24 GB | 26 | all 4K | 23.4 GB |
| RTX 4090 24 GB | 26 | all 4K | 23.4 GB |
| RTX 5090 32 GB | 36 | all 4K | 31.0 GB |
| L40S 48 GB | 52 | all 4K | 44.0 GB |
| A100 80 GB | 94 | all 4K | 78.2 GB |
| H100 80 GB | 94 | all 4K | 78.1 GB |
| RTX PRO 6000 Blackwell 96 GB | 114 | all 4K | 93.8 GB |
| DGX Spark (GB10) 128 GB unified | 131 | all 4K | 107 GB |
| H200 141 GB | 169 | all 4K | 138 GB |
| B200 180 GB | 216 | all 4K | 176 GB |
| Requests at once | 4K tokens each |
|---|---|
| 1 | 2.5 GB |
| 5 | 5.8 GB |
| 8 | 8.2 GB |
| 16 | 14.6 GB |
| 32 | 27.5 GB |
| 64 | 53.3 GB |
One card, with vLLM's small-card settings.
From the model card
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).
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))
StableLM 2 Zephyr 1.6B model is an auto-regressive language model based on the transformer decoder architecture.lm@stability.aiThe dataset is comprised of a mixture of open datasets large-scale datasets available on the HuggingFace Hub:
| Model | Size | MT-Bench |
|---|---|---|
| Mistral-7B-Instruct-v0.2 | 7B | 7.61 |
| Llama2-Chat | 70B | 6.86 |
| stablelm-zephyr-3b | 3B | 6.64 |
| MPT-30B-Chat | 30B | 6.39 |
| stablelm-2-zephyr-1.6b | 1.6B | 5.42 |
| Falcon-40B-Instruct | 40B | 5.17 |
| Qwen-1.8B-Chat | 1.8B | 4.95 |
| dolphin-2.6-phi-2 | 2.7B | 4.93 |
| phi-2 | 2.7B | 4.29 |
| TinyLlama-1.1B-Chat-v1.0 | 1.1B | 3.46 |
| Model | Size | Average | ARC Challenge (acc_norm) | HellaSwag (acc_norm) | MMLU (acc_norm) | TruthfulQA (mc2) | Winogrande (acc) | Gsm8k (acc) |
|---|---|---|---|---|---|---|---|---|
| microsoft/phi-2 | 2.7B | 61.32% | 61.09% | 75.11% | 58.11% | 44.47% | 74.35% | 54.81% |
| stabilityai/stablelm-2-zephyr-1_6b | 1.6B | 49.89% | 43.69% | 69.34% | 41.85% | 45.21% | 64.09% | 35.18% |
| microsoft/phi-1_5 | 1.3B | 47.69% | 52.90% | 63.79% | 43.89% | 40.89% | 72.22% | 12.43% |
| stabilityai/stablelm-2-1_6b | 1.6B | 45.54% | 43.43% | 70.49% | 38.93% | 36.65% | 65.90% | 17.82% |
| mosaicml/mpt-7b | 7B | 44.28% | 47.70% | 77.57% | 30.80% | 33.40% | 72.14% | 4.02% |
| KnutJaegersberg/Qwen-1_8B-Llamaified* | 1.8B | 44.75% | 37.71% | 58.87% | 46.37% | 39.41% | 61.72% | 24.41% |
| openlm-research/open_llama_3b_v2 | 3B | 40.28% | 40.27% | 71.60% | 27.12% | 34.78% | 67.01% | 0.91% |
| iiuae/falcon-rw-1b | 1B | 37.07% | 35.07% | 63.56% | 25.28% | 35.96% | 62.04% | 0.53% |
| TinyLlama/TinyLlama-1.1B-3T | 1.1B | 36.40% | 33.79% | 60.31% | 26.04% | 37.32% | 59.51% | 1.44% |
StableLM 2 Zephyr 1.6B was trained on the Stability AI cluster across 8 nodes with 8 A100 80GBs GPUs for each nodes.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.
Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.