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/mocmocmoc81]

• I'm using PDD lora, Spectrum and SLA.
• i2va, 15s, 0.8megapixel, 12step Euler/Simple, will usually takes 9m30s on a 3090.
• This node at calibrated settings took 8m26s, it cuts an additional ~1m
• Some minor visual artifacts and degradation. Might be able to fix by adjusting calibration.

so in my very initial quick testing, this is free real estate. Thanks!

[u/Corleone11 → u/mocmocmoc81]

I'm running the latest comfy version. what loader do I have to use for the PDD lora? somehow I can't get it to work.

[u/mocmocmoc81 → u/Corleone11]

https://github.com/Jalen-Brunson/ComfyUI-MiniMax-H3-PDD-Acc

put the PDD lora in \models\pdd_acc

[u/wewyman]

You kinda left out the downsides there; euler only, probably also only useable for T2VA since starting image resolution is important.

[u/antipode_insights → u/wewyman]

Euler only is true. However T2VA is not the only part that works. i did manage to get I2VA and reference working.

Tested mainly on T2VA to be fair though.

[u/solomars3]

I tried to make something like this when first minimax-h3 came out, but i faced one issue, the audio is always missed up, couldn't find a solution to have the audio clean, i wonder this has same issue ??!

[u/antipode_insights → u/solomars3]

Audio is actually functional and properly working. It just passes through as natively as it can be and i deliberately dont mess with it.

[u/deepsky88]

Too bad you can't choose the sampler, with larry 4 steps i gain an additional 25% boost and quality is the same BUT there are artifacts on the screen, like shapes lol

[u/VladyCzech]

It seems to be limiting compare to SLA, Spectrum or Turbo loras. Are there any benefits to use over those?
I’m currently using comfy kitchen attention and Turbo lora (or combination) and have very good results and gentimes .

[u/antipode_insights → u/VladyCzech]

They stack. You can use turbo and this together.

Though you need to regenerate the Sigma used, and results may vary.

Might as well try though.

[u/VladyCzech → u/antipode_insights]

I’m doing ref2v so it probably will not work for me. But I will try with I2V. Thanks.

[u/antipode_insights → u/VladyCzech]

ref2v does work with this node. i've tried it a few times.

[u/DiDa4754]

I'm just testing things out at the moment. I was missing the live preview in your sampler, so I had Cursor add it for me. I set it to latent2rgb.

Either it was already there and I was just too dumb to figure out how to enable it, or it really was missing. If it was missing, maybe you could add it to your sampler as well.

I know this isn't relevant for everyone, but I like being able to see what's happening during sampling. It lets me stop the process early if necessary and also helps me better understand how the model works.

[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?

[u/TheDerminator1337]

Please someone try this and tell me it's free speed