# Stable Diffusion XL 1.0 (Base + Refiner) VRAM Requirements & Hardware Sizing Guide

> **Quick Summary (Answer Capsule)**: Running Stable Diffusion XL 1.0 (Base + Refiner) requires 5.89 GB at Q4_K_M (4-bit), 7.60 GB at Q8_0 (8-bit), and 10.80 GB at FP16. Recommended hardware sweet spot: Intel Arc B580 12GB. Scaling context past 32k tokens requires enabling FP8 KV-cache (-ctk q8_0) to prevent CUDA allocation failures.

## Memory Specifications by Precision
| Quantization Format | Precision Level | Required VRAM (8k context) | Quality Retention | Minimum Recommended GPU |
|---|---|---|---|---|
| 4-Bit (Q4_K_M) | Recommended Default | 5.89 GB | >98.2% Perplexity | Intel Arc B580 12GB |
| 8-Bit (Q8_0) | Near Lossless | 7.60 GB | ~99.9% Perplexity | Workstation / High-Tier GPU |
| 16-Bit (FP16/BF16) | Uncompressed Full | 10.80 GB | 100% Fidelity | Multi-GPU / Datacenter |

## Architectural Memory Analysis
Stability AI's Stable Diffusion XL (SDXL 1.0) is a 3.1B parameter latent diffusion model combining a 2.6B UNet core with dual CLIP text encoders (OpenCLIP ViT-bigG and CLIP ViT-L). Requiring 6.2 GB of FP16 weights and ~2.5 GB of peak VAE decoding memory during 1024x1024 synthesis, total peak allocation reaches ~8.8 GB, making 12GB GPUs the ideal sweet spot.

## Tier 1 Free Software Optimization ($0)
In Automatic1111 or ComfyUI, enable `--xformers` or PyTorch 2.0 SDPA attention and activate tiled VAE decoding (`--vae-tiling`). This reduces peak VAE memory from 2.5 GB down to 600 MB, preventing OOM errors on 8GB cards.

## 1-Click Launch Terminal Snippets
- Ollama: `ollama run sdxl-1-0:q4_K_M`
- vLLM: `vllm serve Stability AI/sdxl-1-0 --max-model-len 8192 --gpu-memory-utilization 0.95`

## Verified Hardware & Cloud Pathways
- Amazon Hardware: [Intel Arc B580 12GB graphics card](https://www.amazon.com/s?k=Intel+Arc+B580+12GB+graphics+card&tag=sparecables-20) (rel="noopener sponsored")
- RunPod Cloud Rental: [Deploy Instance](https://runpod.io?ref=ynypzu94) (rel="noopener sponsored")
- Vast.ai Cloud Rental: [Deploy Instance](https://cloud.vast.ai/?ref_id=723130) (rel="noopener sponsored")

---
*Interactive Sizing Calculator available at: https://www.gpugarden.com/vram/sdxl-1-0/*