MiniMax H3 is a 33.1B-parameter omni-modal Transformer that generates video with stereo audio in a single pass. Its hardware bar is lower than the parameter count suggests — the key isn't VRAM alone, but how the three layers of VRAM, system memory and disk work together.
| VRAM | Viable approach | Experience |
|---|---|---|
| 8 GB | GGUF Q3 + heavy offloading + large pagefile | 540p short clips; slow, but it produces output |
| 12 GB | Pruned INT8 (official recommended tier) | 540p–640p; usable after 4–8 step acceleration |
| 16 GB | Same, with more VRAM headroom | 768p short clips feel comfortable; 50-series cards can use NVFP4/W4A8 |
| 24 GB | Full INT8 or larger pruned models | Full-length 768p; layer-by-layer offloading basically unnecessary |
| 32 GB+ | Pruned INT8 resident + NVFP4 encoder | 768p 15-second clips; good for batch rendering |
Note: ComfyUI's dynamic VRAM management lets "peak VRAM" hug the card's limit, so a 16GB card showing roughly 14–15GB of VRAM at 768p is normal — it doesn't mean the model only needs that much.
At runtime H3 has three large blocks competing for memory: the text encoder (14.6–27GB, which doesn't release its host copy after loading), the main model (19.5–34GB), and the VAEs. On a 32 GB machine these can't all stay resident, so the system starts paging in and out — per-step time drops from seconds to tens of seconds, with SSD writes on top.
--fast-disk (so weights live in
reclaimable page cache) and set virtual memory to 48 GB or more; if you use it long-term,
upgrading to 64 GB is the best value step you can take.
The memory generation matters too: dual-channel DDR4-3200 delivers about 36 GB/s of effective bandwidth, while DDR5-6000 delivers about 71 GB/s. In weight-offloading scenarios that gap shows up directly in wait times; single-channel memory halves it again.
| Hardware | Resolution / duration | Steps | Time reference |
|---|---|---|---|
| RTX 5090 32GB | 1344×768 / 5 s | 8 (LightX2V) | ~80 seconds (end-to-end, measured log) |
| RTX 5070 Ti 16GB | 1344×768 / 5 s | 8 (larry) | ~3 minutes |
| RTX 4070 12GB | 576×832 / 5 s | 20 (baseline) | ~4.5 minutes |
| RTX 4070 12GB | 576×832 / 5 s | 4 (LightX2V) | ~80 seconds |
| RTX 3060 12GB | 1280×736 / 5 s | 20 (baseline) | ~17 minutes |
Duration affects time non-linearly: a 15-second video has roughly 3× the tokens of a 5-second one, but attention compute grows quadratically, so the real time gap is larger still. Beginners should start at 5 seconds and stretch it once that works.
The table above is only a reference. Open WhichH3, pick your GPU, memory and pagefile settings, and it will give you the VRAM, RAM, pagefile writes and estimated time for every "resolution × duration" combination, and point out the sweet spot on your machine.