ComfyUI-Precision-Model-Save

ComfyUI Precision Model Save

For users who merge models in ComfyUI and want the saved checkpoint to match the live merged model exactly.

A small custom node for saving a live merged MODEL without using ComfyUI's normal ModelSave materialisation path.

What it does

1. Reads the live patch descriptions from MODEL.get_key_patches().
2. Materialises every merged tensor on CPU in FP32.
3. Casts only the final tensor to your selected file dtype:
   • fp32
   • bf16
   • fp16
4. Saves a standalone .safetensors diffusion model.

The first test should be fp32. It will be roughly twice the size of BF16 and can require a large amount of system RAM while saving.

Install

Extract the folder into:

ComfyUI/custom_nodes/ComfyUI-Precision-Model-Save/

Restart ComfyUI.

The node appears under:

model/merging -> Precision Model Save (FP32 Materialise)

Suggested test

• Feed the exact live merge that produces the expected image into this node.
• Select fp32.
• Keep strip_diffusion_model_prefix = true.
• Save, restart or fully unload models, then load the saved file with Load Diffusion Model.
• Render the same prompt, seed, sampler, scheduler, guidance and steps.

If FP32 matches the live merge while BF16/FP16 drift, the culprit is output precision. If FP32 still differs, the issue is likely not merely the final save dtype.

Important

This is an experimental diagnostic node, not a universal saver. It is designed for ordinary floating-point diffusion models and live ComfyUI model merges. Quantised tensor formats may need architecture-specific handling.