Qwen Image 2512 ModelOpt NVFP4 for SGLang
This repository contains a full Hugging Face-style SGLang Diffusion checkpoint exported from Qwen/Qwen-Image-2512 with NVIDIA ModelOpt NVFP4 quantization support. The checkpoint can be loaded directly with --model-path in SGLang; no separate --transformer-path override is required.
Export provenance
The checkpoint was generated on an NVIDIA B200 machine by applying NVIDIA ModelOpt PR #1706 locally (qwen-image-svdquant-nvfp4-pr) and exporting a full pipeline directory for SGLang validation.
Export settings:
- Base model:
Qwen/Qwen-Image-2512 - Pipeline class:
QwenImagePipeline - Quantization recipe: SVDQuant NVFP4 / FP4 export through ModelOpt
- Main export flag:
--format fp4 - Calibration: max calibration with 8 representative prompts
- Block size: 16
- Quantized scope: diffusion transformer blocks
- BF16 fallbacks: first two and last two transformer blocks, plus attention quantizers disabled during export
- Validation target: NVIDIA B200 / Blackwell using SGLang Diffusion
Validated as a full SGLang Diffusion text-to-image checkpoint on B200 and covered by the SGLang B200 diffusion NVFP4 test.
SGLang usage
sglang generate \
--model-path lmsys/qwen-image-2512-modelopt-nvfp4-sglang \
--prompt "A tiny astronaut reading a book under a glass greenhouse" \
--save-output
For edit pipelines, pass the normal SGLang Diffusion image-edit inputs in addition to --model-path lmsys/qwen-image-2512-modelopt-nvfp4-sglang.
Notes
This is a performance and integration validation checkpoint for SGLang Diffusion NVFP4 support. Please compare generated images with the corresponding BF16 base model for quality-sensitive use cases.