unsloth/MiniMax-H3-FP8

MiniMax-H3, FP8 and INT8

Pre-quantized PyTorch checkpoints of MiniMaxAI/MiniMax-H3, for diffusers plus torchao.

MiniMax H3 is an omni-modal generative system that produces video with native stereo audio, up to 15 seconds at 24 FPS with 32 kHz stereo audio. The files here quantize the fl2va_pruned H3-Base first-and-last-frame variant, which takes zero, one or two input images plus text. Both schemes quantize the same 200 main-block matmuls, 95.8% of the parameters, and leave every 1-D gain, every bias and the whole modulation path bit-identical.

Examples

Same prompt, same seed, same settings, one clip per checkpoint. 960x544, 124 frames, 24 FPS, 8 steps, guidance 1.0, seed 11, on a single card.

a red panda stepping along a mossy log in a misty forest, cinematic

INT8	FP8

The GIFs are downsampled and silent. For the full 960x544 clips with their native 32 kHz stereo audio track, play assets/h3_int8.mp4 and assets/h3_fp8.mp4. H3 generates the audio jointly with the video, so the audio is part of the model output rather than something added afterwards.

Stills from other prompts, three per format:

INT8

FP8

Files

File	Size
MiniMax-H3-INT8.pt	18.86 GiB
MiniMax-H3-FP8.pt	18.87 GiB

Both checkpoints live here, INT8 included. The two are the same repo on purpose: they are one artifact built two ways, and a loader picks between them by filename. Against the 40.23 GB bf16 pruned source either one takes the checkpoint to 20.25 GB and the end-to-end render peak from 57.11 GB to 36.97 GB. Prefer INT8 with torch.compile and FP8 without it.

Both are torchao pre-quantized transformer state dicts, per-output-channel absmax scales, INT8 symmetric and FP8 e4m3. The skeleton is built on meta and the quantized subclass tensors are assigned rather than copied, so dense bf16 never touches the GPU. Each file carries base_model_id = MiniMaxAI/MiniMax-H3 and base_checkpoint = Comfy-Org/MiniMax-H3/diffusion_models/minimax_h3_fl2va_pruned_bf16.safetensors in its metadata, which the loader checks before accepting it.

The source is minimax_h3_fl2va_pruned_bf16.safetensors from Comfy-Org/MiniMax-H3, which already has the modulation pruned to [96768, 8] per block plus a shared adaln_t_table [1025, 8]. Note that stable-diffusion.cpp cannot load these, it has no int8 linear path that reads external per-channel scales, so for sd.cpp use unsloth/MiniMax-H3-GGUF instead.

Licence

MiniMax H3 Community License Agreement, from MiniMax-H3. Full text in LICENSE. Read it before use: it defines an Applicable Territory and excludes some jurisdictions from it. MiniMax also publish a Q&A about the licence.

These files are Model Derivatives, not a plain copy: the transformer is quantized and its modulation is pruned, both of which change the numerics. Section III of the licence wants that stated, so NOTICE lists every change along with the attribution. Not an official MiniMax product, and not endorsed by MiniMax.