GPTQModel

To create a new 4-bit or 8-bit GPTQ quantized model, you can leverage GPTQModel from ModelCloud.AI.

Quantization reduces the model's precision from BF16/FP16 (16-bits) to INT4 (4-bits) or INT8 (8-bits) which significantly reduces the total model memory footprint while at-the-same-time increasing inference performance.

Compatible GPTQModel quantized models can leverage the Marlin and Machete vLLM custom kernels to maximize batching transactions-per-second tps and token-latency performance for both Ampere (A100+) and Hopper (H100+) Nvidia GPUs. These two kernels are highly optimized by vLLM and NeuralMagic (now part of Redhat) to allow world-class inference performance of quantized GPTQ models.

GPTQModel is one of the few quantization toolkits in the world that allows Dynamic per-module quantization where different layers and/or modules within a llm model can be further optimized with custom quantization parameters. Dynamic quantization is fully integrated into vLLM and backed up by support from the ModelCloud.AI team. Please refer to GPTQModel readme for more details on this and other advanced features.

Installation

You can quantize your own models by installing GPTQModel or picking one of the 5000+ models on Huggingface.

pip install -U gptqmodel --no-build-isolation -v

Quantizing a model

After installing GPTQModel, you are ready to quantize a model. Please refer to the GPTQModel readme for further details.

Here is an example of how to quantize meta-llama/Llama-3.2-1B-Instruct:

from datasets import load_dataset
from gptqmodel import GPTQModel, QuantizeConfig

model_id = "meta-llama/Llama-3.2-1B-Instruct"
quant_path = "Llama-3.2-1B-Instruct-gptqmodel-4bit"

calibration_dataset = load_dataset(
    "allenai/c4",
    data_files="en/c4-train.00001-of-01024.json.gz",
    split="train",
).select(range(1024))["text"]

quant_config = QuantizeConfig(bits=4, group_size=128)

model = GPTQModel.load(model_id, quant_config)

# increase `batch_size` to match gpu/vram specs to speed up quantization
model.quantize(calibration_dataset, batch_size=2)

model.save(quant_path)

Running a quantized model with vLLM

To run a GPTQModel quantized model with vLLM, you can use DeepSeek-R1-Distill-Qwen-7B-gptqmodel-4bit-vortex-v2 with the following command:

python examples/deployment/llm_engine_example.py \
    --model ModelCloud/DeepSeek-R1-Distill-Qwen-7B-gptqmodel-4bit-vortex-v2

Using GPTQModel with vLLM's Python API

GPTQModel quantized models are also supported directly through the LLM entrypoint:

from vllm import LLM, SamplingParams

# Sample prompts.
prompts = [
    "Hello, my name is",
    "The president of the United States is",
    "The capital of France is",
    "The future of AI is",
]

# Create a sampling params object.
sampling_params = SamplingParams(temperature=0.6, top_p=0.9)

# Create an LLM.
llm = LLM(model="ModelCloud/DeepSeek-R1-Distill-Qwen-7B-gptqmodel-4bit-vortex-v2")

# Generate texts from the prompts. The output is a list of RequestOutput objects
# that contain the prompt, generated text, and other information.
outputs = llm.generate(prompts, sampling_params)

# Print the outputs.
print("-"*50)
for output in outputs:
    prompt = output.prompt
    generated_text = output.outputs[0].text
    print(f"Prompt: {prompt!r}\nGenerated text: {generated_text!r}")
    print("-"*50)