MiniMax H3 Hardware Guide: From 8GB to 5090
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.
Three numbers to remember first
- 42.5 GB: the on-disk footprint of the smallest usable file combination (pruned INT8 main model 19.5G + NVFP4 text encoder 14.6G + two VAEs totaling 5.4G);
- 12 GB: the lowest practical VRAM tier that can run it (with heavy offloading);
- 64 GB: the "comfort line" for system memory. 32 GB works, but the codecs and the main model can't stay resident at the same time, which makes it noticeably slower.
How the VRAM tiers break down
| 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.
System memory: the bottleneck most people overlook
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.
Rendering time reference (official file combination + acceleration)
| 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.
Get your own numbers from the calculator
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.