An optimized ComfyUI workflow for MiniMax H3, the open-weights omni-modal video model that generates video with native stereo audio in a single pass — up to 2K, 24fps, ~15 seconds a clip. This build is tuned for speed and low-VRAM stability: SageAttention, RTX Video Super Resolution, and a full set of VRAM/RAM cleanup nodes are wired in so the model actually runs on consumer hardware instead of OOM-ing on VAE decode.Runs Text-to-Video (no image connected) and First/Last-Frame Image-to-Video (connect a first frame, last frame, or both) from a single <code>MiniMaxH3ImageToVideo</code> node.<h2 id="run-it-in-the-cloud-(no-local-gpu)">Run it in the cloud (no local GPU)</h2>No GPU with the VRAM/RAM for this? I built a RunPod template that runs this exact workflow in your browser — tested on the 24 GB option: ➡️ <a target="_blank" rel="ugc" href="https://get.runpod.io/Minimax-H3-ComfyUI">https://get.runpod.io/Minimax-H3-ComfyUI</a> (Referral link — you get the signup bonus, I get RunPod credit, no cost to you.)<h2 id="why-this-build">Why this build</h2><ul><li>SageAttention wired in for a ~20-30% speed bump.</li><li>Memory cleanup nodes (🎈VRAM-Cleanup + 🎈RAM-Cleanup) placed to kill the VAE-decode OOM on longer videos and cut RAM usage from ~50 GB to ~30 GB.</li><li>Spectrum-MiniMax-H3 node included for a further claimed ~30% speed gain — worked in my testing, left off the critical path so you can toggle it.</li><li>Resolution Selector locked to H3's native canvas (768px short edge, multiple of 32).</li><li>RTX Video Super Resolution for a clean upscale pass.</li></ul><h2 id="required-models">Required Models</h2>Update ComfyUI to 0.30.0+ first — native H3 support merged Aug 3, 2026.diffusion_models/<ul><li>minimax_h3_fl2va_pruned_int8_convrot.safetensors</li></ul>text_encoders/<ul><li>qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors</li></ul>vae/<ul><li>minimax_h3_video_vae_fp16.safetensors</li><li>minimax_h3_audio_vae_fp32.safetensors</li></ul>All from the <a target="_blank" rel="ugc" href="https://huggingface.co/Comfy-Org/MiniMax-H3">Comfy-Org/MiniMax-H3</a> repo. Both VAEs are required (video + audio). This is the pruned INT8 low-VRAM variant. Tight on memory? Swap only the text encoder for an INT4 build — the INT4 diffusion model quality is poor, so don't swap the main model.<h2 id="custom-nodes">Custom Nodes</h2>Most install via ComfyUI Manager → "Install missing custom nodes": KJNodes · rgthree-comfy · ComfyUI Memory Cleanup · Nvidia RTX Nodes · FearnworksNodes · Spectrum-MiniMax-H3<h2 id="key-tips">Key Tips</h2><ul><li>384p is the floor — 256p fails completely. Start at 0.5 MP preview, confirm your prompt, then scale up.</li><li>System RAM matters as much as VRAM — H3 streams through RAM (~50 GB during gen). Use the cleanup nodes if you're on 32 GB.</li><li>Put the audio in your prompt — dialogue, SFX, and music are generated with the video, so describe them in the same prompt block.</li><li>PyTorch must target CUDA cu30+ for native INT8 ConvRot; older builds fall back to slow software emulation.</li><li>Launch flags: <code>set PYTORCH_ALLOC_CONF=expandable_segments:True</code> + <code>--fast</code> (add <code>--lowvram</code> / <code>--reserve-vram</code> if you OOM).</li><li>Match first/last frame images to your output resolution and aspect ratio for cleaner results.</li></ul><h2 id="credit">Credit</h2>Base workflow adapted from a community post on r/StableDiffusion — full credit to the original author for the initial setup and memory testing. I reorganized the graph and added tweaks. Original: <a target="_blank" rel="ugc" href="https://www.reddit.com/r/StableDiffusion/comments/1vegtac/minimax_h3_tips_and_tricks_and_what_i_experienced/">https://www.reddit.com/r/StableDiffusion/comments/1vegtac/minimax_h3_tips_and_tricks_and_what_i_experienced/</a><h2 id="more-from-me">More from me</h2>🎨 Patreon (free workflows, one-click installers, guides): <a target="_blank" rel="ugc" href="https://www.patreon.com/TheLocalLab">https://www.patreon.com/TheLocalLab</a> ▶️ YouTube (tutorials): <a target="_blank" rel="ugc" href="https://www.youtube.com/@TheLocalLab">https://www.youtube.com/@TheLocalLab</a> 🛒 <a target="_blank" rel="ugc" href="http://locallabdigest.com">locallabdigest.com</a> (installers &amp; digital products): <a target="_blank" rel="ugc" href="https://www.locallabdigest.com">https://www.locallabdigest.com</a>If this workflow helped, a ❤️ or a review is appreciated — it helps others find it.

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