Date: 09.09.2025

Apple M1 16Gb Unified RAM

Limitations

• Apple MPS still about in beta in PyTorch

Test environment

• MBP 16 inch 2021
• Mac OS 15.5
• Python 3.11

MacOS preparation

brew install python@3.11

Dry-run!

Stable Diffusion v1.5

• Preapre python environment for MPS:

mkdir -p ~/llm && cd ~/llm
python3.11 -m venv _venv_llm
source ./_venv_llm/bin/activate
python -m pip install --upgrade pip
pip install torch torchvision torchaudio
pip install transformers accelerate diffusers safetensors
python3 -c "import torch; print(torch.__version__); print(torch.backends.mps.is_available());print(torch.backends.mps.is_built());"

• Get the StableDiffusion 1.5

git lfs install
git clone https://huggingface.co/stable-diffusion-v1-5/stable-diffusion-v1-5 sd1.5

• Create script test_mps_sd1.5.py:

from diffusers import StableDiffusionPipeline
import torch

print("MPS available:", torch.backends.mps.is_available())
print("MPS support:", torch.backends.mps.is_built())

model_path = "/Users/mattcosta/llm/sd1.5"

pipe = StableDiffusionPipeline.from_pretrained(
    model_path,
    torch_dtype=torch.float16,
    safety_checker=None,
    feature_extractor=None,
    use_safetensors=True,
    local_files_only=True
).to("mps")

out = pipe(
    prompt= "cat sitting on a chair",
    height=512, width=512, guidance_scale=9, num_inference_steps=80)
image = out.images[0]

image.save("test.png", format="PNG")

Run test

Check powermetrics during each test while true; do powermetrics --samplers gpu_power -i500 -n1; sleep 1; done

• Run PyTorch

python ./test_mps_sd1.5.py

It works!