| --- |
| license: other |
| license_name: minimax-h3-image-community-license-agreement |
| license_link: LICENSE |
| base_model: |
| - MiniMaxAI/MiniMax-H3-Image |
| base_model_relation: quantized |
| pipeline_tag: text-to-image |
| tags: |
| - comfyui |
| - diffusion-single-file |
| - minimax-h3 |
| - fp8 |
| - nvfp4 |
| - text-to-image |
| - image-editing |
| --- |
| |
| # MiniMax-H3-Image fp8 scaled and NVFP4 (ComfyUI) |
|
|
| Two more precisions of the MiniMax-H3-Image diffusion transformer for |
| ComfyUI, alongside the bf16, int8 ConvRot and w4a8 files in |
| [Comfy-Org/MiniMax-H3-Image](https://huggingface.co/Comfy-Org/MiniMax-H3-Image). |
| They are drop-in replacements for those: same layout, same loader, same |
| workflow. GGUF versions are in |
| [LSDJesus/MiniMax-H3-Image-GGUF](https://huggingface.co/LSDJesus/MiniMax-H3-Image-GGUF). |
|
|
| > **Modified files.** These are quantized versions of MiniMax-H3-Image, made |
| > from Comfy-Org's `minimax_h3_image_pruned_bf16.safetensors`. |
| > MiniMax-H3-Image is licensed under the MiniMax-H3-Image Community License |
| > Agreement, Copyright © 2026 MiniMax. All Rights Reserved. See `LICENSE` and |
| > `NOTICE`. Among other terms, the license grants rights only outside the |
| > European Union, the United Kingdom, South Korea and the United States |
| > (sections I.5 and II), and it includes an acceptable use policy. Read it |
| > before downloading. |
|
|
| ## Files |
|
|
| | File | Format | Size | Runs natively on | Speed | |
| | --- | --- | --- | --- | --- | |
| | `minimax_h3_image_pruned_fp8_scaled.safetensors` | fp8 e4m3, one scale per weight tensor | 21.0 GB | RTX 40 and RTX 50 | 2.1 steps/s | |
| | `minimax_h3_image_pruned_nvfp4.safetensors` | NVFP4 (fp4 with fp8 scales per 16 values) | 12.5 GB | RTX 50 and other Blackwell | 3.4 steps/s | |
|
|
| Speed is sampling at 2048×2048 on an RTX PRO 6000 Blackwell. On the same card |
| Comfy-Org's int8 ConvRot ran 2.6 steps/s and w4a8 2.5. On cards without |
| native support for a format, ComfyUI still runs it, more slowly. |
|
|
| ## Requirements |
|
|
| - **ComfyUI with MiniMax-H3-Image support**, merged on 10 November 2026 |
| (ComfyUI 0.44). |
| - The text encoder (`qwen3vl_32b_minimax_h3_nvfp4_awq` or `_int8_convrot`) and |
| the VAE (`minimax_h3_image_vae_fp16`) from |
| [Comfy-Org/MiniMax-H3-Image](https://huggingface.co/Comfy-Org/MiniMax-H3-Image). |
|
|
| Put the file in `models/diffusion_models/`, open ComfyUI's **MiniMax H3 |
| Image** template and choose it in Load Diffusion Model. |
|
|
| ## What is quantized |
|
|
| The same 200 layers that Comfy-Org quantizes in its int8 and w4a8 files: the |
| fused `qkv_proj`, `out_proj`, `mlp.fc1` and `mlp.fc2` of the 50 transformer |
| blocks, 95.8% of the weights. The token refiner, the condition projection, |
| the adaLN time-curve basis, the patch and output projections and all norms |
| are kept as in the bf16 source, as are the per-block int8 attention setting |
| and the `config` metadata with the 6-step PDD schedule. |
|
|
| - **fp8 scaled**: e4m3 weights with one scale per tensor. `mlp.fc2` is tagged |
| `full_precision_matrix_mult` (fp8 weights, matrix multiply in bf16), as in |
| Comfy-Org's own MiniMax-H3 fp8 files. Its input has outliers that ComfyUI's |
| on-the-fly per-tensor fp8 activation scale cannot hold: without the tag the |
| render drifted far more than NVFP4 (the subject changed and text was |
| misspelled). The other layers quantize their activations on the fly; there |
| are no calibrated activation scales. |
| - **NVFP4**: E2M1 values with an e4m3 scale per block of 16 and one global |
| scale per tensor, made with ComfyUI's comfy-kitchen quantizer. |
|
|
| ## Quality |
|
|
| One render per file, seed 42, 2048×2048, 6 steps, compared with Comfy-Org's |
| int8 ConvRot render. Left: whole image; right: a 1:1 crop. A 6-step model |
| changes its composition a little with any change to the weights, so |
| differences in pose and layout are normal; look for broken texture and text. |
|
|
| The template's own prompt: |
|
|
|  |
|
|
| A held-out photographic prompt (a fruit market with signs): |
|
|
|  |
|
|
