Stable Diffusion 3.5 Large

Stable Diffusion 3.5 Large, released October 22, 2024, is Stability AI's 8B-parameter flagship image model built on the Multimodal Diffusion Transformer (MMDiT) architecture. It was designed to fix SD3's compositional weaknesses — notably prompt adherence and anatomical coherence — and ships alongside Large Turbo (4-step distilled) and Medium (2.5B) variants.

Licensing is the caveat to read carefully: weights are downloadable under the Stability AI Community License, which is free for researchers, developers, and businesses under $1M annual revenue, but enterprises above that threshold need a commercial license. It is not an OSI-open license. The model needs 12GB+ VRAM and benefits from the mature SD ecosystem (ComfyUI, ControlNets, LoRA tooling).