NVIDIA's kitchen-sink framework for speeding up diffusion models
A single PyTorch codebase that distills Stable Diffusion, Flux, DiT, and video models into faster students using half a dozen competing methods.

What it does
FastGen is NVIDIA’s training framework for turning slow, many-step diffusion models into fast few-step generators. It wraps consistency models, distribution-matching distillation, knowledge distillation, and several newer variants into one configurable system. The target models span images (EDM, SD, SDXL, Flux, Qwen-Image) and video (WAN, CogVideoX, Cosmos), with tasks including text-to-image, image-to-video, and video-to-video.
The interesting bit
Rather than championing one distillation technique, FastGen treats them as interchangeable plugins. The same trainer loop runs CM, sCM, DMD2, Self-Forcing, MeanFlow, and others against the same network backends. That design makes it a testbed for comparing methods head-to-head, though the README notes not every method-network pairing is implemented yet.
Key highlights
- Supports models at 10B+ parameters with FSDP2 sharding
- Hydra-style config overrides without editing files (
- key=value) - Built-in EMA, checkpointing, and W&B logging via callbacks
- Docker environment provided; otherwise conda + pip install
- Planned release of distilled CIFAR-10 and ImageNet checkpoints
Caveats
- No pretrained student checkpoints available yet; you train your own
- README warns that “not all combinations of methods and networks are currently supported”
- Video model support appears newer and less battle-tested than image pipelines
Verdict
Researchers and engineers who need to benchmark distillation methods or productionize fast diffusion/video generation should grab this. Casual users looking for drop-in faster models should wait for the promised checkpoint release or look elsewhere.
Frequently asked
- What is NVlabs/FastGen?
- A single PyTorch codebase that distills Stable Diffusion, Flux, DiT, and video models into faster students using half a dozen competing methods.
- Is FastGen open source?
- Yes — NVlabs/FastGen is open source, released under the Apache-2.0 license.
- What language is FastGen written in?
- NVlabs/FastGen is primarily written in Python.
- How popular is FastGen?
- NVlabs/FastGen has 858 stars on GitHub.
- Where can I find FastGen?
- NVlabs/FastGen is on GitHub at https://github.com/NVlabs/FastGen.