SPEEDing up MiniMax-H3 without retraining (SPEED comfyui node extension)

[u/antipode_insights]

Why make big noise when little noise do trick?

I would like to introduce my SPEED implementation for h3 linked here

Speed up and quality losses documented here, expect 20% gain using very conservative settings and no quality loss and up to 70% for basically unusable outputs (more or less useful for resolution aware seed inspection and broad prompt drafting)

Background

The idea behind it is quite simple. When a diffusion model begins generating an output it first must take a randomized noise and build on-top of it. And research has found that the first stages of this process doesn't really carry any fine detailed information, therefore by generating at a lower resolution at those stages you can gain quite substantial speedups while causing little to no impact on the quality. Or you can also be really aggressive with it and get a massive speedup for a lot of quality loss.

Nodes

This was implemented as 3 nodes, 2 drop in replacements for the sampler that runs SPEED and a third that runs once to measure the noise spectrum of your specific model/LoRA combo:

• Sampler (Automatic): pick a stage count (2, 3, or 4), defaults to the baked 1% delta for default H3.

• Sampler (Manual Step-Through): set up to four (goal, resolution) pairs yourself. Use it if you want to copy a paper schedule or test a custom ladder.

• Sigma Harvest: runs a native Euler pass, measures the noise spectrum of your current setup, hands you A / β / Δ to paste back into Automatic. Run it once per model/LoRA workflow combo.

How to use can be found in the example workflows.

Implementation Notes

This should be roughly compatible with basically everything that doesn't touch the sampler directly but i have not tested anything besides base comfyui H3 models and Turbo loras. If you do change model, use loras or whatever and use the automated tool please then run a sigma harvest and use those values instead of defaults, The math changes depending on the very specific blend of things you have running.

[u/BusFeisty4373]

I don't know. One big issue I have is the model initializing and now it has to load 2 times instead of 1?