Can AMD Radeon RX 6800 XT run Stable Diffusion 3.5 Large?
8B parameter Image Gen model on 16GB GDDR6
VRAM Requirements
Stable Diffusion 3.5 Large is a 8B parameter model. At full precision (FP16), it requires 18GB of VRAM. Your AMD Radeon RX 6800 XT has 16GB, so you'll need to quantize it to 8-bit (Q8) to fit.
Maximum quality, no quantization
Near-lossless, ~50% size reduction
Good quality, ~75% size reduction
Recommended system RAM: 32GB DDR5 (2x GPU VRAM minimum for model overflow)
What This Means in Practice
Stable Diffusion 3.5 Large at 8-bit precision on AMD Radeon RX 6800 XT produces images virtually identical to full precision. Generation speed is fast and you'll have some VRAM headroom for larger batch sizes or higher resolutions.
How to Set It Up
Step 1: Install ComfyUI
git clone https://github.com/comfyanonymous/ComfyUI.git && cd ComfyUI && pip install -r requirements.txtComfyUI is the recommended UI for Stable Diffusion and FLUX models.
Step 2: Download the model
Download Stable Diffusion 3.5 Large weights from HuggingFace and place them in ComfyUI/models/. The model is approximately 18GB at full precision.
Step 3: Launch and generate
python main.pyOpen http://localhost:8188 in your browser. You can use the full precision weights.
AMD Radeon RX 6800 XT Specs
Other GPUs That Run Stable Diffusion 3.5 Large
Other Image Gen Models on AMD Radeon RX 6800 XT
About Stable Diffusion 3.5 Large
Latest SD architecture. Better quality than SDXL, slightly more VRAM hungry.