Model reference · open weights

MiniCPM4.1

LLMs openbmb Text gen 1 build Open weights 48k dl/mo

MiniCPM4.1 is an open-weight language model from openbmb. MiniCPM4.1-8B (BF16) weighs 16.4 GB; the smallest configuration that runs it is 2× RTX 3060 12 GB.

  • MiniCPM4.1 is an 8.2B parameter text-generation model developed by openbmb that features trainable sparse attention and supports both deep reasoning and non-reasoning modes.
  • It natively handles a context length of 65,536 tokens and operates in Chinese and English.
  • The model is released under the Apache 2.0 license and is designed for efficient inference with accelerated decoding speeds.

Summary of the openbmb/MiniCPM4.1-8B model card, 2026-10-01

What it is

Released byopenbmb
Released2025-09-02
Parameters8.2B
VRAM16.4 GB for the weights

What it runs on

Memory and cards for MiniCPM4.1-8B (BF16)

16.4 GBweights, file size
33 MBcache per 1K tokens
706 MBruntime overhead, at least
65,536 tokenscontext max
CardRequests at onceContext maxMemory
8K each32K each
RTX 3060 12 GB … RTX 4060 Ti 16 GB
2 smaller cards
———
RTX 3090 24 GB235all 64K23.4 GB
RTX 4090 24 GB235all 64K23.4 GB
RTX 5090 32 GB5112all 64K31.0 GB
L40S 48 GB10025all 64K44.0 GB
A100 80 GB22756all 64K78.2 GB
H100 80 GB21453all 64K78.1 GB
RTX PRO 6000 Blackwell 96 GB27268all 64K93.8 GB
DGX Spark (GB10) 128 GB unified32380all 64K107 GB
H200 141 GB437109all 64K138 GB
B200 180 GB576144all 64K176 GB
2× RTX 3060 12 GB
tensor parallel
205all 64K11.6 GB a card
2× RTX 4060 Ti 16 GB
tensor parallel
4812all 64K15.4 GB a card
Memory needed at each load
Requests at once8K tokens each32K tokens each
117.3 GB18.2 GB
518.4 GB22.4 GB
819.2 GB25.7 GB
1621.4 GB34.3 GB
3225.7 GB51.4 GB
6434.3 GB85.8 GB

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

From the model card

What openbmb says about MiniCPM4.1

Read the model card

👋 Contact us in Discord and WeChat

What's New

  • [2025.09.29] InfLLM-V2 paper is released! We can train a sparse attention model with only 5B long-text tokens. 🔥🔥🔥
  • [2025.09.05] MiniCPM4.1 series are released! This series is a hybrid reasoning model with trainable sparse attention, which can be used in both deep reasoning mode and non-reasoning mode. 🔥🔥🔥
  • [2025.06.06] MiniCPM4 series are released! This model achieves ultimate efficiency improvements while maintaining optimal performance at the same scale! It can achieve over 5x generation acceleration on typical end-side chips! You can find technical report here.🔥🔥🔥

Highlights

MiniCPM4.1 is highlighted with following features:

✅ Strong Reasoning Capability: Surpasses similar-sized models on 15 tasks!

✅ Fast Generation: 3x decoding speedup for reasoning!

✅ Efficient Architecture: Trainable sparse attention, frequency-ranked speculative decoding!

Evaluation Results

Performance Evaluation

MiniCPM4.1 launches end-side versions with 8B parameter scale, both achieving best-in-class performance in their respective categories.

Best Practices

  1. It is advisable to use temperature=0.9, topp=0.95. And we suggest setting max_output_token to 65,536 tokens.
  2. For math problems, we recommend using "Please reason step by step, and put your final answer within \boxed{}."
  3. And for English multiple-choice questions, we recommend starting with "Answer the following multiple choice question. The last line of your response should be of the following format: 'ANSWER: $LETTER' (without quotes) where LETTER is one of ABCD. Think step by step before answering." And "你回答的最后一行必须是以下格式 '答案:$选项' (不带引号), 其中选项是ABCD之一。请在回答之前一步步思考" for Chinese MCQ.

Efficiency Evaluation

MiniCPM4.1 adopts sparse attention and speculative decoding to improve the inference efficiency. On RTX 4090, MiniCPM4.1 achieves 3x decoding speed improvement in reasoning.

Examples

Usage

MiniCPM 4.1 can be used with following frameworks: Huggingface Transformers, SGLang, vLLM, and CPM.cu. For the ultimate inference speed, we highly recommend CPM.cu.

MiniCPM4/MiniCPM4.1 supports both dense attention inference and sparse attention inference modes, where vLLM and SGLang currently only support dense inference mode. If you want to use sparse inference mode, please use Huggingface Transformers and CPM.cu.

  • Dense attention inference: vLLM, SGLang, Huggingface Transformers
  • Sparse attention inference: Huggingface Transformers, CPM.cu

To facilitate researches in sparse attention, we provide InfLLM-V2 Training Kernels and InfLLM-V2 Inference Kernels.

Inference with Transformers

MiniCPM4.1-8B requires transformers>=4.56.

  • Inference with Dense Attention
from transformers import AutoModelForCausalLM, AutoTokenizer
import torch
torch.manual_seed(0)

path = 'openbmb/MiniCPM4.1-8B'
device = "cuda"
tokenizer = AutoTokenizer.from_pretrained(path)
model = AutoModelForCausalLM.from_pretrained(path, torch_dtype=torch.bfloat16, device_map=device, trust_remote_code=True)

# User can directly use the chat interface
# responds, history = model.chat(tokenizer, "Write an article about Artificial Intelligence.", temperature=0.7, top_p=0.7)
# print(responds)

# User can also use the generate interface
messages = [
    {"role": "user", "content": "Write an article about Artificial Intelligence."},
]
prompt_text = tokenizer.apply_chat_template(
    messages,
    tokenize=False,
    add_generation_prompt=True,
)

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

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