Mac 256 GB for local AI
Which image and video models run on an Apple Silicon Mac with 256 GB of unified memory, which file to download for each, and how much of the memory they need.
Specs: support.apple.com
01What runs on it
| Model | Verdict | Best file | Size | Needed |
|---|---|---|---|---|
| image models | ||||
| FLUX.1 [dev] | Runs well | 16-bit | 23.8 GB | 26.1 GB |
| FLUX.1 [schnell] | Runs well | 16-bit | 23.8 GB | 26.1 GB |
| FLUX.1 Kontext [dev] | Runs well | 16-bit | 23.8 GB | 26.4 GB |
| FLUX.1 Krea [dev] | Runs well | 16-bit | 23.8 GB | 26.1 GB |
| FLUX.1 Fill [dev] | Runs well | 16-bit | 23.8 GB | 26.4 GB |
| FLUX.2 [dev] | Runs well | 16-bit | 64.4 GB | 67.7 GB |
| FLUX.2 [klein] 9B | Runs well | 16-bit | 18.2 GB | 20.5 GB |
| FLUX.2 [klein] 4B | Runs well | 16-bit | 7.8 GB | 9.6 GB |
| Krea 2 (Turbo) | Runs well | 16-bit | 26.3 GB | 28.9 GB |
| Qwen-Image | Runs well | 16-bit | 40.9 GB | 43.7 GB |
| Qwen-Image-Edit (2511) | Runs well | 16-bit | 40.9 GB | 43.9 GB |
| Qwen-Image 2.1 | Runs well | 16-bit | 14.2 GB | 16.5 GB |
| Z-Image Turbo | Runs well | 16-bit | 12.3 GB | 14.3 GB |
| Z-Image (base) | Runs well | 16-bit | 12.3 GB | 14.3 GB |
| Ideogram 4 | Runs well | Q8_0 | 10.1 GB | 22.6 GB |
| Boogu-Image (Turbo) | Runs well | 16-bit | 20.6 GB | 23.2 GB |
| ERNIE-Image (Turbo) | Runs well | 16-bit | 16.1 GB | 18.4 GB |
| HiDream-O1-Image | Runs well | 16-bit | 16.4 GB | 19.2 GB |
| Mage-Flow (Microsoft) | Runs well | 16-bit | 8.2 GB | 10.0 GB |
| Lumina Image 2.0 | Runs well | 16-bit | 5.2 GB | 7.0 GB |
| HiDream-I1 (Full) | Runs well | 16-bit | 34.2 GB | 37.0 GB |
| HiDream-I1 (Dev) | Runs well | 16-bit | 34.2 GB | 37.0 GB |
| Stable Diffusion 3.5 Large | Runs well | 16-bit | 16.5 GB | 18.8 GB |
| Stable Diffusion 3.5 Medium | Runs well | 16-bit | 5.1 GB | 6.9 GB |
| Chroma1-HD | Runs well | 16-bit | 17.8 GB | 20.1 GB |
| SDXL 1.0 | Runs well | 16-bit | 6.9 GB | 7.1 GB |
| Illustrious XL / Pony (SDXL anime) | Runs well | 16-bit | 6.9 GB | 7.1 GB |
| Stable Diffusion 1.5 | Runs well | 16-bit | 2.1 GB | 3.3 GB |
| HunyuanImage 2.1 | Runs well | 16-bit | 34.9 GB | 38.2 GB |
| video models | ||||
| Wan 2.1 T2V 14B | Runs well | 16-bit | 28.6 GB | 32.9 GB |
| Wan 2.1 T2V 1.3B | Runs well | 16-bit | 2.8 GB | 5.6 GB |
| Wan 2.1 I2V 14B 480P | Runs well | 16-bit | 32.8 GB | 37.1 GB |
| Wan 2.1 I2V 14B 720P | Runs well | 16-bit | 32.8 GB | 39.6 GB |
| Wan 2.1 VACE 14B | Runs well | 16-bit | 34.7 GB | 39.5 GB |
| Wan 2.2 T2V A14B | Runs well | 16-bit | 28.6 GB | 32.9 GB |
| Wan 2.2 I2V A14B | Runs well | 16-bit | 28.6 GB | 32.9 GB |
| Wan 2.2 TI2V 5B | Runs well | 16-bit | 10.0 GB | 13.8 GB |
| Wan 2.2 Animate 14B | Runs well | 16-bit | 34.5 GB | 39.8 GB |
| Wan Animate 2 (14B) | Runs well | 16-bit | 32.8 GB | 38.1 GB |
| Wan 2.2 S2V 14B | Runs well | 16-bit | 32.6 GB | 37.4 GB |
| SCAIL-2 (character animation) | Runs well | 16-bit | 32.8 GB | 38.1 GB |
| HunyuanVideo (13B, original) | Runs well | 16-bit | 25.6 GB | 29.9 GB |
| LTX-Video 13B (0.9.8) | Runs well | 16-bit | 28.6 GB | 32.9 GB |
| HunyuanVideo 1.5 | Runs well | 16-bit | 16.7 GB | 21.0 GB |
| LTX-2 (19B) | Runs well | 16-bit | 37.8 GB | 42.6 GB |
| LTX-2.3 (22B) | Runs well | 16-bit | 42.0 GB | 46.8 GB |
| LTX-2.5 (22B) | Runs well | 16-bit | 42.0 GB | 46.8 GB |
| MiniMax H3 (33B) | Runs well | 16-bit | 66.3 GB | 72.1 GB |
| MiniMax H3 Pruned | Runs well | 16-bit | 40.2 GB | 46.0 GB |
Calculated from real file sizes plus working memory. How the numbers work.
02Good to know
A Mac with 256 GB shares that memory between the CPU and the GPU. On current macOS the GPU may use about 236.9 GB of it by default (older macOS versions: about 206.2 GB); that is the figure used here. ComfyUI can go past it, but macOS then starts compressing and swapping memory and everything slows down. ComfyUI runs on Apple GPUs through PyTorch's MPS backend. 16-bit and GGUF files work; FP8 and INT8 files do not save memory on a Mac, so they are skipped. Speed is the catch: even the fastest Macs are several times slower per image than a desktop RTX card. Chips sold with 256 GB: M3 Ultra, M5 Ultra (memory bandwidth 819–1200 GB/s — the higher, the faster). Everything about Macs and local AI →
03Measured and reported results
No measured results yet. Send yours.