Qwen3.8-27B — NVFP4 (ModelOpt)

NVFP4 quantization of Qwen/Qwen3.8-27B, produced with NVIDIA TensorRT Model Optimizer 0.45 using NVIDIA's own recipe for the qwen3_5 family (huggingface/qwen3_5/ptq/w4a16_nvfp4-fp8_attn-kv_fp8_cast) — the same mixed-precision scheme NVIDIA used for its official Qwen3.6-27B NVFP4 release:

Component Precision
MLP projections (gate/up/down) + lm_head NVFP4 (W4A16, weight-only, block size 16)
Self-attention and linear-attention (GDN) projections FP8 (E4M3, weights + activations)
KV cache FP8 (constant amax)
Vision tower, MTP head, conv/gating layers BF16 (unquantized)

Checkpoint size is ~21 GB (vs. ~55 GB BF16).

Calibration

Post-training quantization with 1024 samples (max. 512 tokens each), 256 each from four openly available datasets: cnn_dailymail, Magpie-Align/Magpie-Pro-MT-300K-v0.1, nvidia/OpenCodeReasoning, nvidia/OpenMathReasoning. Attention implementation during calibration: SDPA.

Serving with vLLM

vllm serve <this-repo> \
  --quantization modelopt \
  --max-model-len 262144 \
  --reasoning-parser qwen3 \
  --tool-call-parser qwen3_coder \
  --enable-auto-tool-choice

NVFP4 runs natively on Blackwell GPUs; the checkpoint loads on earlier architectures via vLLM's ModelOpt support with reduced benefit.

Notes

  • Community quantization by A2Genesis — not affiliated with or endorsed by the Qwen team or NVIDIA.
  • The MTP (multi-token prediction) tensors are preserved in BF16, so speculative decoding remains available.
  • License: Apache 2.0, inherited from the base model. All credit for the model itself belongs to the Qwen team.
Downloads last month
362
Safetensors
Model size
18B params
Tensor type
BF16
·
F8_E4M3
·
U8
·
Inference Providers NEW
This model isn't deployed by any Inference Provider. 🙋 Ask for provider support

Model tree for a2genesis/Qwen3.8-27B-NVFP4

Base model

Qwen/Qwen3.8-27B
Quantized
(461)
this model