image model · stable-diffusion · macOS
SD Can I run Stable Diffusion 3.5 Large on Apple M3 Ultra (256GB)?
Yes. Stable Diffusion 3.5 Large runs on Apple M3 Ultra (256GB) at Q4 GGUF (~7 GB of ~192 GB usable).
Runs at Q4 GGUF using ~7 GB of ~192 GB usable.
- Peak VRAM
- ~7 GB
- Usable on device
- ~192 GB
- Device memory
- 256 GB
- Quant
- Q4 GGUF
How to run it
Use ComfyUI or Draw Things at Q4 GGUF. The big text encoder is loaded to encode your prompt, then offloaded before generation, which is why peak VRAM stays near the backbone size rather than the sum of every file.
- Type
- image (MMDIT)
- Parameters
- 8.1B
- Peak VRAM
- ~7 GB at Q4 GGUF
- Resolution
- 1024×1024
- License
- Stability Community License
- Memory
- 256 GB unified
- Usable for weights
- ~192 GB
- Best runtime
- MLX direct / Ollama (MLX backend)
You could also run
Run Stable Diffusion 3.5 Large on other hardware
FAQ
Can Apple M3 Ultra (256GB) run Stable Diffusion 3.5 Large?
Yes. Stable Diffusion 3.5 Large runs on Apple M3 Ultra (256GB) at Q4 GGUF (~7 GB of ~192 GB usable).
How much VRAM does Stable Diffusion 3.5 Large need?
Apple M3 Ultra (256GB) has room to spare. At Q4 GGUF the realistic peak is ~7 GB of VRAM, versus ~19 GB with every component kept resident (no offload). With aggressive CPU offload it drops to ~5 GB, much slower.
What do I use to run Stable Diffusion 3.5 Large locally?
Stable Diffusion 3.5 Large runs in ComfyUI or Draw Things (among others). It loads as a diffusion checkpoint plus its text encoder and VAE, not a single chat command.
Sources
VRAM figures are sourced peak-usage anchors at the noted quant, validated 2026-06-15. See methodology.