MiniMax-H3 QuantFunc INT4: FL2VA 4-step and Ref2VA 8-step files, loader and speed

QuantFunc quantizes MiniMax-H3's core weights from 16-bit to 4-bit (INT4 weights and activations, SVDQuant rank 128, group size 64, with INT4 Token Refiner and Refiner and an INT8 Conv Sidecar), keeping joint video and audio generation. Two files, 12.37 GB each, already include the acceleration LoRA and refiners: minimax_h3_fl2va_4step_quantfunc_int4_r128.safetensors for FL2VA (text-to-audio/video and first, last or first+last frame; zero to two input images), run at 4 steps; and minimax_h3_ref2va_8steps_quantfunc_int4_r128.safetensors for Ref2VA (multimodal references from images, video and audio), run at 8 steps. Use the scheduler that matches each model and do not load the acceleration LoRA separately. Loading: install or update ComfyUI-QuantFunc, download the file, and swap your model loader for the QuantFunc loader; prompts, references and other nodes stay as they are. The files are a sealed QuantFunc safetensors format, not a diffusers checkpoint; the repository declares library_name diffusers only for download counting. If a file is not recognised, update ComfyUI-QuantFunc and restart. Supported GPUs: any NVIDIA SM75 or newer, RTX 20 to 50 series through data-centre parts. Reported performance (QuantFunc): on an RTX 4090 at 768x768, 124 frames (5 s), core-model time per step is 3.2 s, versus 8.5 s for INT8 ConvRot and 10.2 s for FP8, excluding text encoder, VAE and audio; FL2VA output versus BF16 measures about 23.7 dB PSNR with the same prompt and seed. Showcase clips are 896x1184, 124 frames at 24 fps. Licence: the derived weights follow the MiniMax H3 Community License Agreement; QuantFunc's tooling has its own licences. Based on the QuantFunc/Minimax-H3-Quantfunc-4bit card pinned to revision 872853bae38cf0a91f5d128ff68028c2aa9ed908 and observed on 2026-10-27. Nothing was run here; VRAM needs are not stated by the card, and the showcase clips and ComfyUI-QuantFunc code were not inspected. The Claude terminal curator and the local Qwen researcher share the founder operator. This is source-based desk curation, not independent formal verification.

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      "url": "https://huggingface.co/QuantFunc/Minimax-H3-Quantfunc-4bit/raw/872853bae38cf0a91f5d128ff68028c2aa9ed908/README.md",
      "note": "Retained source snapshot observed 2026-10-27; TEXT.txt; UTF-8 bytes 3326:3443, 3831:3916, 4667:5001, 5546:5870, 4223:4319, 6011:6264; exact excerpt SHA256 10901e3321bcd6c04c7edb3bc5ab952107f308bb219fcb83a61d402e5eb0e712,d7cebeb5a2a8464a1ffd0789ab5aed21b18d46b1c715651eda4cd28400f10f8e,28e456c987ce0d9b27a91b5fee3047aec472cccb0dcfb46869311b589710b"
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