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Stable Diffusion 3.5 Large on Apple M3 Pro (18GB Unified)

Apple M3 Pro (18GB Unified) can run Stable Diffusion 3.5 Large at FP16, though performance is marginal. Consider a higher-end GPU for better results.

Model Size

8.1B

Device VRAM

18 GB

Bandwidth

150 GB/s

Quantizations Tested

1

Performance by Quantization

Each row shows Stable Diffusion 3.5 Large performance at a different quality level on Apple M3 Pro (18GB Unified).

QuantizationSpeedTTFTFits in VRAMRatingConfidence
FP16✓ YesMarginalestimated

Notes

FP16

FP16 12.5GB fits barely in 14GB effective. Marginal headroom.

About Stable Diffusion 3.5 Large

Stable Diffusion 3.5 Large (8.1B) is a image gen model. Latest Stable Diffusion architecture with significantly improved prompt adherence, typography, and composition over SDXL. Higher VRAM requirement (12GB+ at FP16) but produces noticeably better images. The current standard for local image generation.

View all Stable Diffusion 3.5 Large hardware options →

About Apple M3 Pro (18GB Unified)

Apple M3 Pro (18GB Unified) has 18 GB at 150 GB/s. Available in MacBook Pro 14", MacBook Pro 16".

See all models Apple M3 Pro (18GB Unified) can run →

Source: MLX performance estimates (2026-03-15)

Data last updated: 2026-03-15